Western Toad – Zot Drought Survivor

Toads don’t cause warts.

If your dog tries to eat one, it might foam-at-the-mouth.


With a wide habitat range, western toads can be found from sea level to 11,000 feet elevation and from Baja, Mexico to Alaska.

Like other amphibians, toad numbers have been declining in recent decades, but new field observations give cause for hope. Evidence appears to show that they can adapt to reproducing outside accustomed seasonal cycles and they’ll take advantage of water to breed in, even if it’s not their ‘home water.’

Characteristics & Behavior

Western toads come in a variety of colors – reddish-brown, yellow, green, gray, or white. 

Rough, blotchy bumps can have red centers.  It usually has a light-colored stripe going down the length of its back and large “cheek” glands.

Photo Credit: Spaltedalder

Once a toad leaves its natal water body in spring, they live on the land where they dig shallow burrows, occupy gopher and ground squirrel holes, beaver dams or find protected spaces under rocks or tree roots near water sources such as bogs, streams, meadows, lakes, and rivers. 

Their body temperatures are largely controlled by sun basking and evaporative cooling. In order to avoid drying conditions, they spend the daylight hours on the forest floor in the soil under rocks, logs, stumps, or other surface objects or in rodent burrows.

In June, when temperatures begin to rise, they remain in their burrows, only coming out at dusk or night time to feed.

Like bats, toads have the ability to go into a state of torpor (partial hibernation) during unfavorable living conditions, such as when it’s very hot, cold, or dry. At high elevations, they can go into full hibernation.  (Their blood contains a sugar that acts like antifreeze, protecting organs in extreme cold.)

After waking from winter sleep, western toads migrate back to the water to mate and lay eggs. 

Photo Credit: Steve Collins Valley Conservation

Toads lay eggs in strings, rather than clumps. Hatchlings tend to stay together through metamorphosis.

Tadpole  Diet

  • Suspended plant materials in the water
  • Bottom detritus
  • Carrion

Tadpole Predators

  • Birds
  • Amphibians
  • Mammals
  • Fish

Adult Diet

  • Ants
  • Bees
  • Beetles
  • Butterflies
  • Crayfish
  • Earthworms
  • Fleas
  • Flies
  • Grasshoppers
  • Moths
  • Snails
  • Sowbugs
  • Spiders
  • Slugs
  • Worms

Quick tongue action to catch prey is called a ‘zot’.

*See video in Resources about special saliva.

Adult Predators

  • Ravens, crows, and other birds
  • Snakes
  • Badgers, foxes, bobcats & other mammals

Defense Mechanisms

Peeing and defecating are defense mechanisms. To deter predators, adult toads secrete a mild milky (alkaloid) neurotoxin from glands located on their neck, back, and shoulders. 

Females deposit a small amount of the toxin on newly laid eggs.


 10-11 years


Western toads become sexually mature and able to reproduce between 4 – 6 years old.

Wildlife biologists think toads use smell to travel between breeding territories. They need shallow, open water and tend to return to the same spot each year. 

Unlike other frog species, male western toads do not have vocal sacs. 

Males will compete for a female. Even without a vocal sac, males make a chirping sound as other males approach. He’ll kick competitors away to defend her.

Between March and July, breeding occurs.  Females lay eggs in long strings, up to 17,000 at a time! It takes about three months to complete the metamorphosis from tadpole to toad.

Water temperature regulates metamorphosis speed.


  • Competition with introduced species (not native animals kept as pets and set free)
  • Fungal infection from chytridiomycosis
  • Absorption of fertilizers in water systems
  • Absorption of mineral pollutants from mine water drainage
  • Worm parasites
  • Habitat destruction
  • Warming water temperatures

Toads & Dogs – Tips to Reduce the Possibility of Poisoning

  • Don’t leave pet water (or food) outside. Toads are attracted to it.
  • If a toad has soaked in your pet water, it could make your pet sick.

Signs of Toad Poisoning

Signs that your dog has tried to eat a toad include;

  • Foaming-at-the-mouth is a sign that your pet may have tried to eat a toad.
  • Pawing at the mouth
  • Excessive drooling
  • Pet might vomit it swallowed a whole toad

If you saw where it happened, it’s a good idea to – carefully – retrace your animal’s steps to verify the cause. (Always be aware that rattlesnakes can also be a possibility!)

 Most U.S. toads are only mildly toxic (highly toxic varieties live in Hawaii, Southern California, Arizona, New Mexico and along the Colorado River). 

Poisoning First Aid  

If your pet is conscious;

  • Rinse mouth with a hose pointing from the back of the mouth out, nose tipped down.
  • If possible, don’t let your animal swallow the flush water.
  • Don’t induce vomiting unless instructed by your vet.
  • Continue rinsing for 5 to 10 minutes

Call your vet.

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If you liked this article, you may also like Sierra Newt – Powerful Water Drive & Deadly Skin or Sierran Tree Frog with Chemical Sensitivities 


Anphibiaweb.org – Anaxyrus boreas 
ASPCA – The Trouble with Toads: Getting to the Bottom of this Toxic Threat
CaliforniaHerps.com – Boreal Toad – Anaxyrus boreas
California Herps – Identifying Toads in California
Canadian – Western Toads 

Core.AC.UK – Late-season Reproduction in Western Toads (Bufo boreas) PDF [2017] 
Global News – Hop to it: Whistler park closed as 40K baby toads hit the road in mass migration
Habitat Conservation Trust Foundation – Toadlet Migration 2018 Update (Canada)
National Geographic Education – Conserve Western Toad (Canada) 
National Park Service – Amphibian Monitoring 
National Park Service – Drought Uncovers New Facts About West Coast Toads 
National Park Service – A Need to Breed: California Toads in the Santa Monica Mountains


The University of British Columbia – Roseanna Gamlen-Greene Western Toad Ecology
USDA Forest Service – Anaxyrus boreas – fire effects information 
Wikdipedia.org – https://en.wikipedia.org/wiki/Western_toad

Mountain Lion – Fragmented Power Pouncer


Wikipedia commons

Since the late 1850’s, North America’s big cat has been known as the mountain lion. Early Spanish explorers called it ‘gato monte‘ which means cat of the mountain.

Latin America calls it puma (powerful) which comes from the 16th century Peruvian Quechua language.

Because of its wide range, diverse habitats, and the span of human cultural locations, this animal is known by many other names including; cougar, panther, and catamount.

Geographic Habitat

California’s current mountain lion population is between 4,000 – 6,000 animals.

Closely related to the house cat, these big cats are adaptable to a large variety of ecosystems. In the Nevada County portion of the Sierra Nevadas, they like dense underbrush and rocky outcropping habitats.

Highly territorial, males generally claim a 150 square mile area that may vary depending on terrain and prey availability. Females have smaller territories, about half the size, and they stay in the general proximity of their mothers.


“Wherever you see deer in the state, there’s also going to be cougars.”  – Chris Wilmers, Wildlife Ecologist, UC Santa Cruz


  • Mountain lions are the world’s fourth-largest big cat weighing between 150 – 200 lbs. (1. Siberian Tiger | 900 lbs. 2. African Lion | 600 lbs. 3. Jaguar | 300 lbs.)
  • While the mountain lion is an apex predator, it will sometimes give ground to black bears.
  • These cats can swim, although this is not a favorite activity.
  • Hunting mostly during twilight hours and at night, mountain lions are ambush predators. They sit-and-wait, often in concealment, before launching a fast surprise attack.
  • With large paws and powerful hind legs, they’re sprinters that can run between 40 – 50 miles per hour.

Jumping Adaptation

Mountain lions can jump as high as seven queen-sized beds, stacked length-wise, end-to-end. This makes getting into trees easy and is an ambush asset.


  • Traditionally thought to be solitary predators, biologists are currently studying complex family structures.
  • Mountain lions will reciprocally share kills within small communities controlled by dominant males.
  • Mountain lions can kill prey with a single bite to the neck, positioning teeth into the spinal cord between vertebrae.
  • These animals cache their meals. After a kill, they’ll bury the prey and continue visiting the carcass for up to a week. 
  • Males use feces and urine to scent-mark a territory, often scraping leaves and grass into a pile and urinating on it.
  • Young males searching for territory are more likely to fight and cause livestock problems.
  • Mountain lion relocation causes territory disruption, resulting in aggressive behaviors, and conflicts with established males.

Vocalizations are Mostly for Family

Humans may never know about lion neighbors, partly because we don’t recognize their vocalizations.

With other animals, scent marking is the main mode of mountain lion communication.  Within family units, mothers and kittens make a variety of noncat-like sounds.

Mothers make sounds to call for and locate kittens and kittens make distress calls that are answered by their mothers.

Purring may be sibling competition for food.

Caterwauling is used by females mostly in heat.


Mountain lions are obligate carnivores, they must eat meat to survive. Generally, they need to make one large kill (deer) every two weeks.  However, females raising kittens may need to make more frequent kills – every three days.

For an adult, average daily meat consumption is up to 10 lbs.

Food sources include;

  • deer
  • fox
  • skunk
  • rabbits
  • coyote
  • raccoons
  • river Otter
  • bobcat
  • squirrels
  • woodrats
  • rats and other rodents
  • any animal it can catch including livestock and housepets

In a Sonoma County study,

75% of mountain lion diet was deer,

10% livestock, 10% feral and house cats,

and 5% small mammals.


  • Females reach reproduction age between one-and-a-half and three years. Occasionally couples are monogamous, but more often mountain lions mate with multiple partners. During mating, a couple will remain together for about a week. After mating, the males go back to their own territory.
  • Gestation is approximately 3 months.
  • Females will have litters of 1-6 cubs, with an average of about 2. They’ll give birth every 2-3 years.
  • Cubs are born blind.
  • Nursing lasts up to 3 months.
  • Cub survival rate is slightly over kitten one per litter.
  • Kittens have spots for up to about 2 1/2 years.
  • Females raise their kittens alone.
  • Only mothers and offspring spend time together in social groups.
  • Juveniles remain with their mother from 1 1/2 – 2 years, until she’s ready for her next litter.

Photo credit: Eric Kilby

When kittens are nursed, the mother will bring meat to them. As they get older, she takes them to kill sites. Older still, they begin hunting small mammals on their own.

Photo credit: National Parks Service

Causes of Kitten Mortality

  • coyote
  • bear
  • hypothermia
  • wildfires
  • male mountain lions

Habitat Fragmentation A Breeding Problem

Southern California mountain lion studies reveal that male lions must have the ability to safely move between wide swaths of land to access and breed with diverse female populations.

With movement constricted by busy freeways, inbreeding occurs. This genetically weakens populations.

Mountain lion inbreeding tail deformities
Crooked tails are a genetic defect from inbreeding. Article: Genetic Connectivity Threatens a Southern California Puma Population by Ernst, Vickers, Morrison & Boyce

Experts believe if inbreeding continues, the Southern California mountain lions will go extinct within in the next 50 or 60 years.

Mountain lion inbreeding tail deformities
Ten genetic populations of California mountain lions (marked by color) Mountain Lion Foundation | mountainlion.org

Life Span

In the wild, the average mountain lion life span is between 8-13 years. In captivity, they’ve been known to live up to 21 years.

Predators & Threats

  • Genetic isolation & inbreeding (habitat fragmentation).
  • Rodenticides (rat and mouse poisons) traveling up through the food chain.  (In a study of 400 mountain lion necropsies, 95% showed some degree of poisoning.)
  • As habitats are encroached upon by humans, mountain lions are coming in contact with and susceptible to feline leukemia, rabies, and other infections.
  • Cars (roadkill).
  • Man and kill permits.

Nevada County Mountain Lion Kill Permits 2011-2019

Nevada County Mountain Lion Depredation Statistics 2011-2019 PDF

What Humans Can Do to Successfully Live in Lion Territory

Since we live in mountain lion territory, we should always assume we have an invisible mountain lion in our backyard and behave accordingly.

  • Don’t use anticoagulant rodenticides.
  • Value and support local and state policies aimed toward mountain lion conservation.
  • Never feed deer or other wild animals and encourage neighbors to do the same. (Wild animals who’ve lost natural fear of humans become a public safety issue, resulting in animal extermination.)
  • Fire safety – removing dense, low-lying vegetation close to your house – is identical for mountain lion safety.
  • Plant deer-resistant plants.
  • Consider outdoor automatic lighting.
  • Reduce driving speeds in wildlife zones, being especially from dawn to dusk.
  • Don’t litter and/or pick up roadside litter.
  • Don’t leave pet food outside.
  • Secure garbage on pick-up days.
  • Don’t let pets roam free.
  • Train guard dogs to watch-over livestock.
  • Build mountain lion resistant (very tall) livestock shelters.
  • Don’t put meat in compost piles.
  • Establish wildlife passage corridors to accommodate animal migration and movement.

Prevent Mountain Lion Encounters

  • Hike in groups.
  • Carry sticks.
  • Don’t bend down to tie shoes.
  • Make lots of noise.
  • Keep children walking in front of adults and within sight.
  • Carry pepper spray.
  • Keep dogs leashed. (A loose, running dog stimulates mountain lion chase behavior. If under pursuit, your pet will bring the chase straight to you!)

Attacks on Humans are Rare

Attacks on humans are very rare! The natural behavior for a mountain lion is to run away.

If a lion doesn’t run immediately;

  • Make sure it isn’t cornered.
  • Be big and loud.
  • Pull your jacket above your head.
  • Don’t crouch down or run.
  • Pick up children and back away.
  • Don’t make intense eye contact.

If it comes to a physical encounter, attempt to;

  • Fight back with rocks and sticks.
  • Stay on your feet.
  • Yell.
  • Protect your neck.

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If you like this article, you may also like Coyote the Ultimate Adaptor.



Audubon Canyon Ranch – Living with Lions: ACR’s mountain lion research and education project
Bay Area Puma Project
BBC – What it’s like living in California’s mountain lion country [2017] – When a kill permit is issued
California Department of Fish and Wildlife – Commonly Asked Questions about Mountain Lions
California Department of Fish and Wildlife – Mountain Lion
California Department of Fish and Wildlife – Mountain Lion Depredation Statistics Summary
California Department of Fish and Wildlife – Verified Mountain Lion-Human Attack in California [ Two fatalities statewide in 34 years] California Mountain Lions – film & miniseries
CBS Denver – Dog Owner Says Lesson Learned After Encouonger with Moutain Lion [2016]

Conserving Connectivity: Some Lessons from Mountain Lions in Southern California, Morrison, Scott A. and Boyce
Conservation Society of California – Oakland Zoo – Mountain Lion Initiative The Cougar Conundrum: Sharing the World with a Successful Predator by Mark Elbroch | Revelator Article – What’s the Value of a Mountain Lion?
Los Angeles Times – After a nuisance mountain lion was killed, two L.A. city leaders wan to end the practice [2020] Los Angeles Times – Southern California mountain lions get temporary endangered status [2020] Mercury News – Mountain lions get endangered species protections in California
Mountain Lion Foundation
The Nature Conservancy – Animal Tracks 
National Geographic – Exploring the use of five type os puma vocalizations
NPR – The Secret, Social Lives of Mountain Lions | radio program 3:49
Sacramento Bee – California voters banned mountain lion hunting three decades ago, but the killing never stopped [2017] Smithsonian Magazine – California Will Build the Largest Wildlife Crossing in the World [2019] Liberty Canyon Wildlife Crossing PDF

Sonoma West – Living with mountain lions [2019] UC Davis Puma Project – New Study Details the Double Lives of Surburban Pumas [2004] UC Santa Cruz – Power of the pounce 
Wikipedia.org – Cougar

Predator Proofing for Livestock & Pets:

Preditor Proof Pens

Wildlife Rescue | Sonoma County | Puma Proof Pen

Tail Flashing Cache Faker – Western Gray Squirrel


The Western Gray Squirrel is a tree (arboreal) rodent and is the largest of its kind in the Sierra Nevada Mountains weighing between one-half to two pounds. Tree squirrels like dense cover in which to travel across branches, build several kinds of nests, and seek safety. They live at nearly every elevation in Nevada County. Favorite trees are the black oak.


Like crows and ravens, tree squirrels are keen people watchers. If you live in their territory, chances are they know a lot more about you than you do about them. Active during the day, squirrels understand human activity patterns and they can recognize the people who feed them and the people who thwart them.

In spring they undergo a full body molt and in fall a neck to rump molt.  


As with the North American Beaver, Porcupine, and other rodents, a squirrel’s teeth grow continuously. They must gnaw and chew to keep them from getting too long.

When a Wester Gray Squirrel finds a nut, it will roll it for approximately twenty seconds. Biologists think the animal is evaluating the quality of the nut -if it should be eaten immediately or cached away for winter. 

Twenty-second nut roll. Behavior thought to be nut quality evaluation. Eat now or cache for later.

The cache fake-out happens when a squirrel pretends to bury a nut – with other squirrels watching – then moves to another place to actually burry it. Another impressive aspect of squirrel behavior is their ability to memorize the location of their caches. 

(Eastern Gray Squirrel - identified by brown fur around eyes - shown in video)

Many tail uses;

  • blanket
  • blood coolant
  • climbing counterbalance
  • raincoat
  • communication

If a squirrel holds its tail in an S shape, it’s feeling threatened. It waves it to look larger.

Another special skill is leaping up trees, all four paws raise at the same time, but it happens so quickly it’s difficult to see. When going down a tree, their back feet rotate so claws act as anchors. 

Leaping. Photo Credit: Dan Johnson

When traveling long distances, a squirrel’s preferred travel mode is from branch to branch, high off the ground. When foraging for food, or hurrying between caches, they will scamper on the ground, but at the first sign of danger, back to tree safety they go! 

Native Western Gray Squirrels need a continuous stretch of mature oak trees for survival. 

‘Sleep rough’ is thought to be a method of temperature control. This is when a squirrel lays on its belly, spread out as much as possible. Often they’ll do this on branches but it’s also been observed on the ground, on the picnic tables, or anywhere that is squirrel appealing.

Sleeping rough is thought to be a behavior that helps regulate body temperature.

Defense Behavior

Western Gray Squirrels work cooperatively like many prey animals to sound alarm warnings. 


(Fox Squirrel shown in video)

In the winter, squirrels don’t hibernate but they do slow down. This is when nut caches are consumed.


  • acorns
  • pine nuts
  • new leaf buds
  • fruit
  • bird eggs
  • seeds
  • small birts
  • fungi
  • bark
  • sap
  • insects

Raiding bird feeders is summer fast-food. As winter approaches, they devote more time to scatter-hoarding.

*Forgotten caches help trees grow in new locations. 

Western Gray Squirrels compete for the same food sources as the acorn woodpecker, ground squirrels, and other introduced squirrel species (S carolinensis and S. niger).

Life Span

7-8 years


Breeding happens in late spring starting at about a year old. A female signals readiness with enlarged, pink vulva and a male with a scrotum that turns from pink to black. The act of mating is vigorous and taxing.

Nesting mothers use their own molted hair to line the nest (drey). She’ll also use shredded bark, moss, and lichens.

Gestation is about 43 days. Younger females will have smaller litters compared to more mature breeding females who average between 3 – 5 hairless kits. Babies nurse for about two months but stay in the nest for about six months total. Tails don’t fill out until babies are out of the nest.

The second type of nest build by Wester Gray Squirrels is a sleeping platform, it is not as enclosed as the birthing nest and is for temporary use.  


  • bobcats
  • coyote
  • foxes
  • owls
  • hawks
  • house cats

Habitat Threats

  • urbanization habitat loss
  • roadkill
  • wildfires
  • fire suppression management
  • overgrazing
  • scotch broom invasive species
  • mite diseases
  • competition with introduced squirrel species and wild turkeys

If you liked this post, you may also like Einstein Corvidae – Crows and Ravens

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Agility test

Bay Nature – Are Fox Squirrels Replacing Gray Squirrels in California?

iNaturalist – Western Gray Squirrel

Phys.org – Squirrels have a long memory for problem solving

U.S. Fish & Wildlife Service – Conboy Lake (WA) – Western Gray Squirrel

Wikipedia – Western Gray Squirrel





Western Fence Lizard – Three-eyed Push-Up Tyrant with Break-Away Body Parts

The western fence lizard is also known as a blue-belly because of the brightly colored scales under its throat and at the outer edges of the underbelly. It is a fossorial (burrowing) poikilotherm (an animal that regulates body temperature by sun basking or dirt burrowing).

In females and youngsters, the blue markings are faint or not there at all.


This lizard measures 2 inches to 3.5 from nose to snout. Eight inches total, including the tail.

Because of its pointed, overlapping scales, it’s a member of the spiny lizard genus –  Sceloporus.

Colors range from sandy, black, brown to green. Some may have back stripes. Under the arms may be yellowish. Western fence lizards have the ability to change colors. Biologists think this adaptation relates to maintaining body temperature rather than for camouflage.

Third Eye

The third or parietal eye is located at the top of the lizard’s head. It’s covered by a translucent scale. Its purpose is to sense light throughout the year, signal the onset of reproduction and it helps control body temperature.


The length of winter hibernation is dependent on climate conditions.


  •  Fast, biting, and defecating on predators
  • Dropping tail – caudal autotomy or self-amputation (Scientists measure from snout to vent because of the break-away tail)



Functions of the Push-ups;

  • courtship – fitness demonstration – the more brilliant colors, the healthier the male (low parasite load)
  • territorial defense display – in mating season, males defend an approximate 25-foot radius from a high perch
  • may also relate to food availability within the territory
  • a dominant male guarding at the highest point in the territory is known as a tyrant 


A blue-belly’s favorite food is insects. It will eat beetles, grasshoppers, ants, wasps, aphids, mosquitoes, ticks, scorpions, centipedes, and spiders. It will also eat other western fence lizards! 


As they grow, lizards shed skin in pieces. Sometimes, it becomes a snack. Successful shedding depends on diet, health status, and environmental conditions.

Life Span

5-7 years


Birds, snakes, alligator lizards, and cats.

Male Identification 

Like birds, male western lizards are more brightly colored and showy than females. Where the tail meets the body, males have two large scales near the vent, a single opening used for waste elimination and reproduction.

While copulating, the male’s blue color is at its most brilliant.


Male identification at 2:17

Western fence lizards begin breeding after one year.

Mating Season – March – June

Egg size is largest with the first clutch. The number of clutches laid in a season depends on temperature and elevation. At lower elevations, females will lay between 1-4 clutches. At higher elevations, they’ll lay between 1-3 clutches. Each clutch can contain between 3-17 eggs.

Eggs and Hatching

Eggs incubate for approximately 2 months. Once hatched, babies fend for themselves.


Disease Benefits to Humans

Western fence lizards have a protein in their blood that filters out the spirochete bacterium in Deer Ticks that cause Lyme disease. After a tick feeds on a lizard it will not spread Lyme disease to its next, larger, host during its life cycle.


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If you liked this post, you may also like Deer Tick, A Questing Blood Sucker



Bay Nature – How You Can Tell Male from Female Lizards? 

In Tech Open – Reptilian Skin and Its Special Histological Structures

John Muir Laws – Lizards, Ticks, and Lyme oh my! (audio)

MonkeySee – How to Care for Pet Lizards (video)

Natural History Museum of Los Angeles – ‘Tis the Season fo Baby Lizards

Purdue University – Shedding Reptiles (PDF)

Reptilian Third Eye

San Francisco State University – Department of Geography –   The Biogeography of  Sceloporus occidentalis

Sci Show – How Do Animals Re-Grow Limbs (And Why Can’t We?)

UC Berkeley News – Tick population plummets in absence of lizard hosts

University of California Agriculture & Natural Resources – Pests in Gardens and Landscapes – Lizards
Lizards cause no measurable damage to plants in gardens and may be beneficial by eating pest insects and should be left alone.”

BioWeb – Western Fence Lizard

WIRED – Lizards Use Third Eye to Steer by the Sun

Wikipedia – Western Fence Lizard 

Porcupine – Pointed Payback for Getting Too Close

If you’re lucky enough to see one of these shy nocturnal rodents, don’t worry. It won’t charge or shoot sharp darts. If your dog sees it, his/her up-close canine curiosity may result in a painful payback.

Deer Creek Porcupine Spotters Needed!

According to the Nevada County Resource Conservation District and Wikipedia’s List of Mammals of California porcupines should live in the Deer Creek watershed. However, recent  iNaturalist observations (2019-2020) only show sightings in the Sutter Buttes and around Truckee. The California Department of Fish and Wildlife is asking the public to log sightings. (See last paragraph below.)

Red dots show 2019-2020 iNaturalist North American Porcupine observations. The aqua strip shows the location of the Deer Creek watershed.

Historic Names

  • Thorn pig
  • Quill pig

These animals are north American’s second-largest rodent after the beaver.

MYTH CORRECTION: Porcupines don’t shoot quills

Hair, Quills, Stink & Antibiotic Skin

Most of the animal is covered guard hair that looks like quills. Quills are located in a structure, called the rosette, on the animal’s back-side. It flares out – like a dog raising hackles – when the rodent feels threatened. In order to become stuck by the quills, the threatening animal must press against the rosette which triggers quill release. Porcupines will also do tail slaps, similar to beavers, as a warning or with direct contact. Smartly, they aim for the face!

Quills are lightweight and hollow. In addition to defense, they also help the porcupine stay warm in cold weather.

Within the rosette is skin that produces a noxious odor – R-Delta-Decalactone- a waxy grease that spreads to nearby quills and hair. It emits a stink cloud announcing the animals’ presence, especially at night.  Folks familiar with the smell say it’s similar to strong body odor or soft cheese.

Photo Credit: Rob Routledge, Sault College, Bugwood.org

Medical researchers are studying quill barb designs for an alternative to surgical staples (see articles in Resources below).

According to Dr. Uldis Roze, who was punctured by a quill that traveled up his arm, porcupines produce antibiotic chemicals that coat their quills. It’s a defense against self-injury., a common occurrence when porcupines fall from trees.

Additional Defenses

In addition to quills and a stink that grows stronger with fear, it’s black and white coloring and teeth clacking are also defense mechanisms.


North American Porcupines are nearsighted, slow-moving, and solitary. During the day they spend most of their time in trees. In winter, they’ll hang out near their den.


The North American Porcupine is an herbivore. Below is a list of food sources.

  • roots
  • twigs
  • stems
  • nuts
  • berries
  • grasses
  • tree bark
  • conifer needles

Porcupines crave salt. Campers, backpackers, forestry and road workers say they can be found along snowy roadsides looking for salt. They’ve also been known to chew sweat-soaked socks, boots, gloves and wooden tool handles. They’ll also chew on plywood for the salty-tasting chemicals added.

Photo Credit: Dave Powell, USDA Forest Service (retired) Bugwood.org
Photo Credit: Photo Credit: Rob Routledge, Sault College, Bugwood.org






Den and Scat


  • coyote
  • wolf
  • black bear
  • mountain lion
  • golden eagle
  • great horned owl


Mating begins in the fall high up in tree branches. To signal receptivity, the female excretes a strong odor – a mixture of urine and mucus. Males arrive and wait. If multiple show up, they fight for dominance.

When the winner approaches the female in the tree, he spritzes her with urine which begins a chemical reaction sending her into full estrus. To complete the process, they move to the ground where female holds her quills flat against her body and lifts her tail so as not to injure the male.

Porcupine Mating in a Zoo

Compared to other rodents, North American Porcupine mothers are pregnant for 202 days.  (A female beaver carries for 128 days.)

They give birth to one soft-quilled procupette at a time. Quills harden after birth. A porcupine mother will nurse her young for up to four months.

Young are full-grown in two years.

Mothers care for youngsters but do not defend them from predation.

Life Span

If they are not hunted by humans, poisoned, killed by cars or die of starvation, a healthy North American Porcupine can live up to 30 years.

Human Uses for Porcupines

Native Americans have traditionally used porcupine quills for decoration and warmth.

Hunters eat them and farmers have exterminated them as pests.

California Department of Fish and Wildlife (and iNaturalist)

“Observations of porcupines in recent years have become relatively uncommon and DFW is soliciting sightings from the public. In California, porcupines are most common in montane conifer and wet meadow habitats, and can be found in the Coast Ranges, Klamath Mountains, southern Cascades, Modoc Plateau, Sierra Nevada, and Transverse Ranges.” – CDFW

Report a North American Porcupine sighting for the California Department of Fish and Wildlife here

Report a North American Porcupine sighting on iNaturalist (California Academy of Sciences & National Geographic)

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Chicago Tribune – Heal Thyself, Oh Fat and Prickly Porcupine

Cleveland Museum of Natural History

CPR News – Porcupine Barbs for Better Wound Healing

Discovery Magazine – Why Porcupine Quills Slide in with Ease but Come Out with Difficulty

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Live Science – Porcupine Facts

National Library of Medicine – Antibiotic Properties of Porcupine Quills

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North County Public Radio – Porcupine Quills Like Hairs, Like Feathers












Porcupine Stink

Proceedings of the National Academy of Sciences of the United States of America – Microstructured barbs on the North American porcupine quill enable easy tissue penetration and difficult removal

Removing Porcupine Quills – Quills Can Travel Through the Body

Seeker – Porcupine Quills Inspire Medical Devices





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