Category: Animals

Animals are multicellular, eukaryotic organisms in the kingdom Animalia, characterized by their ability to move voluntarily (at least at some life stage), lack of cell walls, and heterotrophic nutrition, meaning they consume other organisms or organic matter for energy. They range in size from microscopic plankton to massive blue whales, occupying nearly every habitat on Earth—land, sea, air, and even extreme environments like deep-sea vents or polar ice. Animals exhibit diverse forms, from simple sponges with no true tissues to complex mammals with advanced nervous systems. Most reproduce sexually, though some, like certain jellyfish, can reproduce asexually. They play critical roles in ecosystems as predators, prey, pollinators, and decomposers. Behaviors vary widely, from solitary hunters like tigers to highly social species like ants. Major groups include mammals, birds, reptiles, amphibians, fish, and invertebrates like insects and mollusks, each adapted to specific ecological niches.

Zebra Tailed Lizard ( Callisaurus draconoides )

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The Zebra-Tailed Lizard is a medium sized lizard which features a long black and white striped tail and commonly found in California, Arizona and Nevada. Additional coloring includes two rows of brown / bray spots down the middle of the back, and is often marked with cream colored spots. The males boast belly bars which range in color from blue to yellow and orange. The females belly bars are often much more muted or lacking completely.

A male Zebra-Tailed Lizard ( Callisaurus draconoides )
A male Zebra-Tailed Lizard ( Callisaurus draconoides )

This animal is commonly between 4 and 6 inches in length from snout to vent and its regenerative tail may double to overall length of this animal. The female lays a clutch of up to 15 eggs, however the more common number is between 2 and 8 eggs. A healthy population will host between 4 and 6 lizards per acre, however the number seems much higher when they are darting around you in the Mojave, Great Basin or Sonaran deserts

The Zebra tails are frequently found at elevations up to 5,000 feet. The are usually found in areas which have sandy soils and open spaces in which they can run. An ambush predator, the lizard will often lie in way for its dinner to walk by and is known to feed on bees, wasps, beetles, caterpillars, ants and grasshoppers. Additionally it is known to consume other small lizards and spiders.

Very tolerant of the high heat of the desert in which it lives, the feisty lizard is known to be active during the high temperatures of the summer sun when most animals seek shade and go underground. These lizards are know to alternately stand on opposing feet and alternate between then two stances as a means of protection from the harsh landscapes in which it lives. During the cooler nights, the lizard may burrow down into fine sane, however is also known to sleep on the surface on warm nights.

When spotted by a predator, the reptile will curl its boldly stripped tail over its head which may serve notice to the predator that it was spotted. When needed a quick burst of speed will serve as the best prevention to being a meal to larger animals.

A Zebra Tailed lizard photographed ny my lovely wife in the Ivanpah Mountains of California.
A Zebra Tailed lizard photographed ny my lovely wife in the Ivanpah Mountains of California.

Black Tailed Jackrabbit ( Lepus californicus )

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The Black-tailed Jackrabbit (Lepus californicus), a swift and adaptable lagomorph of the American West, is often mistaken for a rabbit but is technically a hare, known for its enormous ears, powerful hind legs, and distinctive black-tipped tail. This species thrives in open, arid environments, where its speed—reaching up to 40 mph (64 km/h)—and evasive maneuvers make it a master of survival against predators like coyotes and eagles. With a mottled gray-brown coat providing camouflage against dusty landscapes, the black-tailed jackrabbit plays a key role in ecosystems as both prey and herbivore, influencing vegetation dynamics across its range.

Black Tailed Jackrabbit enjoying the shade of a Joshua Tree
Black Tailed Jackrabbit enjoying the shade of a Joshua Tree.

Classification

The Black-tailed Jackrabbit is classified within the kingdom Animalia, phylum Chordata, class Mammalia, order Lagomorpha, family Leporidae, and genus Lepus. Its scientific name, Lepus californicus, reflects its association with California, though its range extends far beyond. It is one of several North American hares, distinguished from true rabbits by its larger size, longer ears, and precocial young (born fully furred and mobile). Subspecies include variations adapted to different regions, such as L. c. californicus in coastal areas and L. c. deserticola in deserts. Fossil records trace its lineage to the Pleistocene, highlighting evolutionary adaptations to open habitats post-Ice Age.

Physical Description

Adult Black-tailed Jackrabbits measure 47–63 cm (18–25 inches) in body length, with ears extending 10–13 cm (4–5 inches), and weigh 1.4–3.6 kg (3–8 lbs), with males typically larger than females. Their fur is grizzled gray-brown on the upper body with white underparts, providing effective camouflage in scrubby terrain. The namesake black tail is white underneath, flashed as a warning signal during flight. Oversized ears, richly vascularized, aid in thermoregulation by dissipating heat, while large eyes positioned on the sides of the head offer nearly 360-degree vision for detecting threats. Long, powerful hind legs enable explosive leaps up to 3 meters (10 feet) high and 6 meters (20 feet) long, complemented by furred soles for traction on varied surfaces. Juveniles resemble adults but are smaller and fluffier at birth.


IUCN Red List of Threatened Species, species assessors and the authors of the spatial data.

Behavior

Black-tailed Jackrabbits are primarily crepuscular and nocturnal, active during dawn, dusk, and night to avoid midday heat and predators, though they may forage diurnally in cooler weather. They are solitary except during breeding, maintaining home ranges of 0.1–1 square km (25–250 acres) that overlap with others. When threatened, they rely on speed and zigzag running patterns to evade pursuit, often freezing in place first to blend into surroundings before bolting. They spend much of the day in shallow depressions called “forms,” often under shrubs for shade and cover, emerging to forage. Communication is limited, involving thumping hind feet as alarm signals and scent marking with chin glands. In extreme heat, they pant and use their ears to cool blood; in cold, they huddle to conserve warmth. Populations fluctuate cyclically every 7–10 years, influenced by food availability, disease, and predation.

Food Sources

As herbivores, Black-tailed Jackrabbits have a diet dominated by grasses, forbs, and shrubs, adapting seasonally: green grasses and herbaceous plants in spring and summer, and woody twigs, bark, and dried vegetation in fall and winter. Favorites include alfalfa, clover, sagebrush, and mesquite, with agricultural crops like wheat and lettuce targeted in farmlands, sometimes making them pests. They obtain most water from food, rarely drinking, and can consume up to 1 kg (2.2 lbs) of vegetation daily. Their caecotrophic digestion—re-ingesting soft feces (cecotropes)—allows extraction of additional nutrients like proteins and vitamins from low-quality forage. This adaptation is crucial in nutrient-poor arid environments.

Breeding

Breeding in Black-tailed Jackrabbits is promiscuous and occurs year-round in southern ranges, peaking from December to September in northern areas, triggered by rainfall and food abundance. Females, or does, reach sexual maturity at 7–8 months, males slightly later. Courtship involves chasing and “boxing” displays where pairs rear up and strike with forepaws. Gestation lasts 41–47 days, with litters of 1–8 leverets (average 3–4), born in shallow forms lined with fur. Precocial young are born with open eyes, full fur, and mobility, weaning at 3–4 weeks and independent by 1–2 months. Females can produce 3–4 litters annually, leading to high reproductive rates that offset heavy predation.

Habitat and Range

Black-tailed Jackrabbits inhabit open, arid to semi-arid landscapes including desert scrub, prairies, grasslands, farmlands, dunes, and shrub-steppe, preferring areas with short vegetation and minimal dense understory for easy escape routes. They avoid closed-canopy forests and high elevations above 3,000 meters (9,800 feet). Their range spans the western United States from central Washington eastward to Missouri, southward through the Great Plains and Southwest to Baja California Sur and Zacatecas in Mexico, with introductions in some eastern states. Populations are non-migratory but may shift locally with food availability. Human activities, like agriculture, have expanded suitable habitats, though habitat loss and fragmentation pose threats in some areas.

Classification

Kingdom:Animalia
Phylum:Chordata
Class:Mammalia
Order:Lagomorpha
Family:Leporidae
Genus:Lepus
Species:L. californicus

Desert Horned Lizard (Phrynosoma platyrhinos)

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Desert Horned Lizard (Phrynosoma platyrhinos)
Desert Horned Lizard (Phrynosoma platyrhinos)

Desert Horned Lizard (Phrynosoma platyrhinos), also known as the “horny toad”, is a common North American reptile and found throughout the southwest and the Mojave. A personal childhood favorite of mine, the horned lizard does have the appearance of a small dinosaur and it a master of camouflage.

This is a small to medium sized lizard, its 3 – 5 inch broad and flat body features a prominent series of fringed scales. Its head also boasts several horn which offers the lizard its name. Undoubtedly, the overall body shape is that of a toad is also a contributing factor. The coloration of the body will vary to help the lizard blend into its background.

The reptile’s diet is small insects and is commonly found at or near ant mounds where they will lie in wait for its meal to simply walk by. Generally speaking this animal is found at elevations below 6500 feet in creosote-bursage flats and Mojave Desert Scrub.

Desert Horned Lizard, a master of camouflage
Desert Horned Lizard, a master of camouflage

Defensively, the little lizard is all about appearances. Primarily, camoflauge allows it to remain hidden in plain sight. The reptile is known to hiss and puff up its chest when confronted in an effort to appear larger and more dangerous that it really is known to be. Some species of the genus are known to squirt blood from its eyes and may reach a distance of 5 feet.

Mustang (Equus ferus caballus)

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The Wild Mustang (Equus caballus), an enduring symbol of the American frontier, roams the vast, arid expanses of the desert southwest United States as a feral horse population descended from domesticated Spanish horses introduced in the 16th century. These hardy equines, often romanticized in folklore and media, have adapted through natural selection to survive in harsh environments, exhibiting remarkable resilience amid sparse resources and extreme conditions. With populations managed by the U.S. Bureau of Land Management (BLM) to balance ecological sustainability, mustangs embody a complex interplay of history, biology, and conservation in regions like Nevada, Arizona, and New Mexico.

A lone mustang is the symbol of wild, power and freedom
A lone mustang is the symbol of wild, power and freedom

Classification

The Wild Mustang is classified within the kingdom Animalia, phylum Chordata, class Mammalia, order Perissodactyla, family Equidae, genus Equus, and species caballus. Though often referred to as “wild,” mustangs are technically feral horses, descendants of domesticated equines rather than a truly wild subspecies like the extinct North American horses that evolved on the continent millions of years ago. Their ancestry traces primarily to Colonial Spanish horses from the Iberian Peninsula, with mitochondrial DNA studies confirming high frequencies of Iberian haplotypes, though admixtures from other breeds like Thoroughbreds, Quarter Horses, and drafts have occurred over time. Distinct strains, such as the Spanish Mustang or Kiger Mustang, retain stronger Spanish bloodlines, while isolated herds in the desert southwest may exhibit unique genetic traits shaped by geographic separation and natural selection.

Physical Description

Mustangs are compact, medium-sized horses, typically standing 14 to 15 hands high (56 to 60 inches or 142 to 152 cm at the withers) and weighing around 800 pounds (360 kg). They possess a light-riding build with muscular bodies, strong bone structure, and exceptional hardiness, featuring flat or slightly convex head profiles, broad foreheads tapering to fine muzzles, and eyes set slightly higher on the face. Necks are well-defined and attach smoothly to sloping shoulders, with moderately narrow chests, short strong backs, deep heart girths, well-sprung ribs, and smooth round hindquarters. Legs are straight and sound, supported by durable hooves with thick walls, ideal for rugged terrain. Coat colors vary widely, including bay, sorrel, dun, appaloosa, paint patterns, and primitive markings like stripes, though some registries exclude certain patterns like tobiano. Movement is smooth and rhythmic, with the ability to gallop at 25–30 mph (40–48 km/h), and up to 55 mph (88 km/h) in short bursts. In the desert southwest, natural selection favors traits like surefootedness, endurance, and agility for navigating arid landscapes.

Behavior

Wild mustangs are social animals that form structured groups known as bands or herds, typically comprising one dominant stallion (over 6 years old), around eight mares, and their young, led by a head mare who guides the group to safety in threats while the stallion defends from behind. Stallion leadership is dynamic, with challenges from rivals promoting genetic diversity. Communication relies on body language, such as ear positioning, tail swishing, and vocalizations, to convey emotions and maintain hierarchy. They exhibit intelligence, curiosity, and a strong fight-or-flight response honed by survival in harsh environments, making them cautious yet resilient. In the desert southwest, mustangs travel long distances for resources, adapting foraging strategies and mixing with other herds during dangers. Isolated populations may show unique behaviors, like gaited movements or curly coats in Nevada herds, influenced by genetic admixtures. Without significant predators, populations can grow rapidly, leading to overgrazing if unmanaged.

A mustang taking in some shade next to a pool of water.
A mustang taking in some shade next to a pool of water.

Food Sources

As herbivores and hindgut fermenters, mustangs primarily consume grasses, brush, shrubs, and other native vegetation, extracting nutrients from low-quality forage via their cecum—a adaptation allowing survival in arid regions where ruminants like cattle struggle. In the desert southwest, they graze close to the ground on sparse plants, ranging 5–10 times farther than cattle to access food and water, often digging for hydration in dry areas. Their diet requires about 1.5 animal units (AUM) of forage, focusing on soluble fiber while avoiding excess sugars to prevent digestive issues. An average mustang needs around 16 pounds of grass daily, supplemented by minerals and salts in harsh environments. This opportunistic foraging supports their easy-keeper nature, enabling them to thrive on limited resources in deserts and grasslands.

Breeding

Mustangs are viviparous, with mares carrying foals for an 11-month gestation period, typically giving birth in spring (April to June) to align with milder weather and abundant forage for growth. Breeding occurs within isolated herds, where dominant stallions mate with mares, and dynamic challenges ensure genetic diversity, though inbreeding in small populations can lead to issues like reduced heterozygosity and diseases such as PSSM Type 1. Unmanaged herds can grow by up to 20% annually, prompting BLM interventions like fertility control to prevent overpopulation and starvation. Foals are born precocial, able to stand and nurse shortly after birth, and remain with the herd for protection. In the desert southwest, breeding success ties to resource availability, with natural selection favoring resilient offspring in arid conditions. Lifespans in the wild reach up to 36 years, shorter than in captivity.

Two will fed mustangs near Cold Creek, Nevada
Two will fed mustangs near Cold Creek, Nevada

Habitat and Range

Wild mustangs inhabit arid and semiarid public rangelands west of the Continental Divide, including deserts, grasslands, and mountainous terrains, where they adapt to extreme temperatures, scarce water, and sparse vegetation. In the desert southwest United States, populations thrive in states like Nevada (hosting over half of North America’s free-roaming mustangs), Arizona, New Mexico, Utah, and California, managed across 26.9 million acres in Herd Management Areas (HMAs) by the BLM. These areas encompass ecosystems from the Great Basin to the Colorado Plateau, with herds digging for water and migrating seasonally for forage. Total free-roaming numbers exceed 72,000, protected under the 1971 Wild Free-Roaming Horses and Burros Act as living symbols of the West, though overpopulation challenges lead to roundups and adoptions.

BLM Mustang Range Map
BLM Mustang Range Map

Resources

Classification

Kingdom:Animalia
Phylum:Chordata
Class:Mammalia
Order:Perissodactyla
Family:Equidae
Genus:Equus
Species:E. ferus
Subspecies:E. f. caballus

Speckled Rattlesnake ( Crotalus mitchellii )

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The Speckled Rattlesnake is fairly common pit viper found in southern California, southern Nevada, western Arizona and south-western Utah and down the Pacific coast into Baja California.  A moderate size snake, this animal typically does not exceed 39 inches in length.  As with most animals, the Speckled Rattlesnake is a master of disguise and commonly are colored to compliment the surrounding rock.  This viper can range from pink, cream, tan or pale blues and grays.  This feature I can personally attest to as I witnessed and entire Cub Scout Pack literally step over the specimen photographed below while hiking on a camping trip in the Valley of Fire State Park just outside of Las Vegas, Nevada.

Juvenile Speckled Rattle Snake found in Valley of Fire State Park, Nevada
A Juvenile Speckled Rattlesnake found in Valley of Fire State Park, Nevada
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