Collared Lizard Size: How Big Collared Lizards Get

Collared lizard size is one of the first questions people ask after spotting one of these bright, boulder dwelling lizards in the American Southwest. A full grown Crotaphytus collaris reaches roughly 20 to 38 cm in total length, tail included. It typically weighs between 45 and 120 grams.

This guide covers snout vent length versus total length and how males and females compare. It also covers growth rate and how the species stacks up against its closest relatives in the genus Crotaphytus.

How Big Do Collared Lizards Get

Total length combines two different numbers. Snout vent length (SVL) is the body from nose to the base of the tail. The tail itself is often longer than the body.

Herpetologists measure SVL separately because tails break and regrow. That would otherwise skew size comparisons over time.

Published total length figures for Crotaphytus collaris span 20 to 38 cm. A small adult is close to the length of a dollar bill. A large one approaches 15 inches nose to tail tip.

Body mass tracks with length but varies more. A well fed lizard before egg laying can weigh noticeably more than a lean one in early spring. The 45 to 120 gram range covers healthy wild adults across the species’ range.

That range spans Ozark uplands to Sonoran Desert scrub. A lizard under 45 grams is usually a juvenile, not an underweight adult.

State field guides agree closely with those figures. The Missouri Department of Conservation gives adults of the eastern collared lizard as 8 to 14 inches in total length, with a head that is large for the body. The difference at the top end reflects the largest desert males, which Missouri’s glade populations rarely match.

Males vs Females: Collared Lizard Weight and Length

Male collared lizards run larger than females, a pattern seen across the genus. Males carry a broader head and heavier jaw muscles, used in territorial combat. They also show the bold black collar bands and turquoise to yellow green body color that give the species its name.

Females stay smaller. Their collar is browner and less contrasty most of the year. It becomes brighter only briefly, when a female is gravid and develops orange side blotches.

The size gap is moderate, not extreme. A keeper or field observer comparing two lizards side by side can usually spot the male first. Its head is larger and its build bulkier, even before checking collar color.

Collared Lizard Growth Rate: Hatchling to Full Grown

The growth calendar starts with breeding from mid May to early June. Females lay 4 to 24 eggs within 20 days of mating, and some lay a second clutch. Eggs incubate for 2 to 3 months, so hatchlings appear from late summer into early fall and stay active through October.

Hatchlings emerge at a small fraction of adult size and grow quickly through their first active season. The Animal Diversity Web notes that young collared lizards can roughly double in body size during their first year. Missouri’s field guide puts sexual maturity within the first or second year of life.

Growth continues after that, at a slower pace. Like most lizards, Crotaphytus collaris shows indeterminate growth, meaning it does not stop lengthening once mature. The window to reach full size is short, since wild individuals rarely live past 5 years.

Size and growth rate connect closely to how long a species lives overall. See the lizard lifespan guide for how collared lizard growth patterns compare to other species.

• Hatching: late summer to early fall, well under half of adult length.
• First year: rapid growth, potentially doubling in size.
• First or second year: sexual maturity reached; growth continues but slows.
• Adulthood: full grown total length of 20 to 38 cm; growth nearly stops but never fully halts.

Crotaphytus Species Sizes Compared

The genus Crotaphytus holds several collared lizard species across the Southwest and northern Mexico. Size data is not equally complete for all of them.

The table below lists what authoritative sources confirm. Rows are left out rather than filled with a guess.

Snout vent length and total length are not interchangeable. That is why the table separates them by measurement type rather than forcing every species into one column. Across the family, collared lizards sit on the smaller end.

Leopard lizards of the related genus Gambelia tend toward the larger end of that shared size range. See how their proportions differ on the leopard lizard species page.

What Affects Collared Lizard Size

Diet quality and prey availability explain much of the variation within a single population. A lizard hunting abundant grasshoppers and beetles through a wet summer typically grows larger than one from a lean, dry year. Details on what and how often they eat are on the collared lizard diet page.

Geography plays a role too. Populations range from Missouri and Arkansas rock glades to Arizona and New Mexico desert scrub. Different growing seasons, temperatures and prey bases shift the average size within local populations, even though the species wide range stays 20 to 38 cm.

In captivity, enclosure setup and feeding schedule influence growth in a similar way. General husbandry basics are on the collared lizard care page.

For range, identification and a full species overview beyond size alone, see the main collared lizard page.

Legal Status and Welfare: Should You Keep a Wild Collared Lizard

Collared lizards are a wild native species, not a captive bred pet line. Rules on collecting or keeping one taken from the wild vary by state. Some states allow limited, licensed collection of native reptiles; others restrict or ban it outright.

Missouri, for example, lists the eastern collared lizard as a Species of Conservation Concern, since it was once rare there before glade restoration in the 1980s and 1990s rebuilt its numbers. Anyone considering keeping a wild collared lizard should contact their state wildlife agency directly and confirm current rules first. Never look for ways around a state’s collection rules.

The Red List assessment for Crotaphytus collaris lists the species as Least Concern, with no federal protection or CITES listing noted. A healthy conservation status at the species level does not make collecting legal everywhere. Removing lizards from rocky outcrop habitat can still affect a local population, especially where development or drought has already reduced numbers.

The most honest welfare answer is to leave wild collared lizards where they are. Photograph them and watch their push up territorial displays from a respectful distance. Handling a wild lizard also risks tail loss, since the tail detaches easily as a predator defense and only partially regrows.

If a captive collared lizard is wanted, look for a reputable breeder producing captive bred animals instead of a wild caught one.

The species is not venomous, though any bite should still be cleaned. More detail is on the collared lizard bite and venom page.

Frequently Asked Questions

How big do collared lizards get?

Adult collared lizards reach a total length of about 20 to 38 cm (8 to 15 inches), tail included. They weigh roughly 45 to 120 grams. Males typically finish larger and heavier than females.

What is a collared lizard full grown weight?

A full grown collared lizard weighs about 1.6 to 4.2 ounces (45 to 120 grams). Body condition shifts that number seasonally. A lizard is heaviest after a summer of good insect hunting and lightest coming out of winter dormancy.

Do male or female collared lizards grow bigger?

Males grow larger overall, with a broader head and heavier build tied to territorial defense. The size difference is moderate, not dramatic. Collar color and pattern remain the more reliable way to sex an individual.

How fast does a collared lizard grow?

Hatchlings grow quickly and may roughly double their body size in the first year. Missouri’s field guide puts sexual maturity within the first or second year, and wild lifespan rarely past 5 years. Growth continues after maturity but slows year over year.

Is it legal to keep a wild collared lizard?

Rules on collecting native reptiles vary by state and sometimes by county, so there is no single nationwide answer. Check directly with the relevant state wildlife agency before collecting one. Default to leaving wild lizards in their habitat.

How does collared lizard size compare to other lizards?

Collared lizards sit in the mid range among common desert lizard species. They run larger than most small skinks or anoles but smaller than large monitors or iguanas. See a broader size rundown on the types of lizards guide.