Animal Diversity Web

Ge­o­graphic Range

Cro­ta­phy­tus col­laris, com­monly known as the east­ern col­lared lizard, is a species of lizard that is pri­mar­ily found in North Amer­ica and open areas of Mex­ico. Its range in Mex­ico in­cludes parts of the states of Chi­huahua, Coahuila, Du­rango, Nuevo Leon, San Luis Po­tosi, Tamauli­pas, and Za­cate­cas. The ge­o­graphic range of C. col­laris is rel­a­tively large and en­com­passes sev­eral states and re­gions within the United States. The species is pri­mar­ily dis­trib­uted through­out the cen­tral and east­ern re­gions of the United States, in­clud­ing parts of Texas, Ok­la­homa, Kansas, Ne­braska, Mis­souri, Arkansas, Louisiana, Mis­sis­sippi, Al­abama, Ten­nessee, Ken­tucky, In­di­ana, Illi­nois, and Ohio. It is also found in iso­lated pop­u­la­tions in south­west­ern Iowa, south­east­ern Col­orado, and west­ern Geor­gia. ("East­ern Col­lared Lizard", 2022; "Field Guide to North Amer­i­can rep­tiles and Am­phib­ians", 1997; Glos­sip and Losos, 2002)

• Biogeographic Regions
• nearctic
  • native

Habi­tat

Cro­ta­phy­tus col­laris in­hab­its arid and semi-arid re­gions of the south­west­ern United States and north­ern Mex­ico. This species is com­monly found in rocky, sparsely veg­e­tated habi­tats, par­tic­u­larly in areas with abun­dant boul­ders, rocks, and other rocky out­crops.

Cro­ta­phy­tus col­laris oc­cu­pies a wide range of habi­tat types, in­clud­ing desert scrub­lands, grass­lands, shrub­lands, and wood­lands, often in close prox­im­ity to rocky areas. They occur at el­e­va­tions rang­ing from 150 to 2400 me­ters above sea level, with its ter­res­trial level being pre­dom­i­nantly found in the low to mid el­e­va­tions. ("East­ern Col­lared Lizard", 2022; "Field Guide to North Amer­i­can rep­tiles and Am­phib­ians", 1997; Glos­sip and Losos, 2002)

• Terrestrial Biomes
• desert or dune
• savanna or grassland
• forest
• scrub forest

• Range elevation

  150 to 2400 m

  492.13 to 7874.02 ft

Phys­i­cal De­scrip­tion

Adults are ec­tother­mic and typ­i­cally range from 20 to 38 cen­time­ters, with males being slightly larger than fe­males. Adult weight ranges from 45 to 120 grams, with males being higher in the weight range. Their ap­pear­ance is dis­tinc­tive, with a flat­tened body, large head, and long, pow­er­ful legs. They have a promi­nent, banded col­lar around their necks, which is black in males and brown in fe­males. Their backs are cov­ered in small, keeled scales that give them a rough tex­ture, while their bel­lies are smooth and light-col­ored. The color of their skin varies de­pend­ing on the re­gion they are found in, but they typ­i­cally have a brown­ish-gray color with darker brown or black mark­ings.

Ge­o­graphic vari­a­tion has been re­ported in Cro­ta­phy­tus col­laris, with in­di­vid­u­als from dif­fer­ent re­gions hav­ing slightly dif­fer­ent col­oration and pat­tern­ing. Sea­sonal vari­a­tion has also been ob­served, with in­di­vid­u­als in breed­ing sea­son dis­play­ing brighter col­ors and more pro­nounced col­lar mark­ings. Sev­eral sub­species of Cro­ta­phy­tus col­laris have been de­scribed, in­clud­ing C. c. bai­leyi, C. c. flavoviridis, and C. c. melanomac­u­la­tus. These sub­species dif­fer in their ge­o­graphic dis­tri­b­u­tion, col­oration, and pat­tern of mark­ings.

Poly­mor­phisms, or the ex­is­tence of mul­ti­ple forms within a species, have not been re­ported in Cro­ta­phy­tus col­laris. How­ever, young an­i­mals dif­fer from adults in their col­oration and mark­ings. Ju­ve­niles have a brighter col­oration, with more vi­brant red and or­ange mark­ings on their backs and tails. As they ma­ture, these col­ors be­come muted and blend in with their over­all col­oration.

Cro­ta­phy­tus col­laris can be dis­tin­guished from other closely re­lated species, such as the west­ern col­lared lizard Cro­ta­phy­tus in­su­laris bicinc­tores, by their dis­tinct col­lar mark­ings and the shape of their heads. The east­ern col­lared lizard has a wider head with a more pro­nounced jaw­line, while the west­ern col­lared lizard has a more elon­gated head with a nar­rower jaw­line. Ad­di­tion­ally, the col­lar mark­ings of the east­ern col­lared lizard are thicker and more promi­nent than those of the west­ern col­lared lizard. ("COL­LARED LIZARD", 2023; "Field Guide to North Amer­i­can rep­tiles and Am­phib­ians", 1997; J. E, 1992)

• Other Physical Features
• ectothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger
• sexes colored or patterned differently

• Range mass

  45 to 120 g

  1.59 to 4.23 oz

• Range length

  20 to 38 cm

  7.87 to 14.96 in

De­vel­op­ment

After mat­ing, the fe­males lay a clutch of 1 to 8 eggs in a bur­row or crevice, which she then cov­ers with soil. The eggs in­cu­bate for around 55 to 65 days, de­pend­ing on the tem­per­a­ture and hu­mid­ity of the nest en­vi­ron­ment. Dur­ing this pe­riod, the em­bryos de­velop and grow in­side the egg.

Once the eggs hatch, the hatch­lings emerge from the nest and begin their jour­ney to­wards adult­hood. Ju­ve­niles re­sem­ble adult lizards in their ap­pear­ance and be­hav­ior but are smaller in size. They grow rapidly and shed their skin fre­quently to ac­com­mo­date their ex­pand­ing bod­ies.

Col­lared lizards do not un­dergo meta­mor­pho­sis. They ma­ture di­rectly from the hatch­ling stage to the adult form. The rate of mat­u­ra­tion and growth of col­lared lizards de­pends on var­i­ous fac­tors such as tem­per­a­ture, diet, and habi­tat con­di­tions.

The sex of col­lared lizards is de­ter­mined by the tem­per­a­ture at which the eggs are in­cu­bated. The eggs in­cu­bated at a tem­per­a­ture range of 28-30°C pro­duce males, while eggs in­cu­bated at tem­per­a­tures be­tween 30-32°C pro­duce fe­males.

Cro­ta­phy­tus col­laris ex­hibits in­de­ter­mi­nate growth, mean­ing they con­tinue to grow through­out their lifes­pan. The rate of growth, how­ever, de­creases with age, and they even­tu­ally reach a max­i­mum size. (Clark, 2002; "Field Guide to North Amer­i­can rep­tiles and Am­phib­ians", 1997; J. E, 1992; Sloan, 1996; Timanus, 2001)

• Development - Life Cycle
• temperature sex determination

Re­pro­duc­tion

Cro­ta­phy­tus col­laris is a polyg­y­nous species, where one male mates with mul­ti­ple fe­males. The mat­ing sea­son of C. col­laris gen­er­ally oc­curs dur­ing the spring and sum­mer months, but can vary de­pend­ing on the ge­o­graph­i­cal lo­ca­tion and en­vi­ron­men­tal con­di­tions.

Mat­ing be­hav­ior in col­lared lizards be­gins with males es­tab­lish­ing ter­ri­to­ries and ac­tively search­ing for re­cep­tive fe­males. Males en­gage in vi­sual dis­plays to at­tract fe­males, in­clud­ing head-bob­bing, push-ups, and dis­play­ing their brightly col­ored throat (dewlap) to sig­nal their avail­abil­ity and fit­ness.

Once a male en­coun­ters a fe­male, he may court her with fur­ther vi­sual dis­plays and phys­i­cal con­tact, such as nuz­zling or bit­ing the fe­male's neck or tail. Fe­males may re­ject or ac­cept mat­ing at­tempts from males, and mul­ti­ple males may com­pete for a sin­gle re­cep­tive fe­male.

Male C. col­laris de­fend their ter­ri­to­ries and mate-guard re­cep­tive fe­males to pre­vent other males from mat­ing with them. These ter­ri­to­r­ial be­hav­iors can re­sult in so­cial struc­tures where dom­i­nant males con­trol larger ter­ri­to­ries and have ac­cess to more fe­males. ("Adult male col­lared lizards, Cro­ta­phy­tus col­laris, in­crease ag­gres­sion to­wards dis­placed neigh­bours", 2003; Clark, 2002; "Field Guide to North Amer­i­can rep­tiles and Am­phib­ians", 1997; Sloan, 1996)

• Mating System
• polygynous

Cro­ta­phy­tus col­laris breeds once a year, gen­er­ally oc­curs dur­ing the spring and sum­mer months, with fe­males lay­ing 1 to 8 eggs per breed­ing sea­son. The eggs are in­cu­bated for ap­prox­i­mately 55 to 65 days, and the hatch­lings emerge fully formed and in­de­pen­dent at birth. The species reaches sex­ual ma­tu­rity at around 2 to 3 years of age and can breed an­nu­ally. (Clark, 2002; Glos­sip and Losos, 2002; Sloan, 1996; Timanus, 2001)

• Key Reproductive Features
• seasonal breeding
• sexual
• fertilization
• oviparous

• Breeding interval

  Crotaphytus collaris breeds once a year

• Breeding season

  Crotaphytus collaris breed during the spring and summer months

• Range number of offspring

  1 to 8

• Average time to independence

  0 days

• Average age at sexual or reproductive maturity (female)

  2-3 years

• Average age at sexual or reproductive maturity (male)

  1-2 years

Cro­ta­phy­tus col­laris is an oviparous species and does not ex­hibit any parental care or in­vest­ment be­yond the ini­tial pro­duc­tion and de­po­si­tion of eggs. Once the fe­male has laid her eggs, she does not pro­vide any fur­ther care or pro­tec­tion to them, and the hatch­lings are fully in­de­pen­dent and self-suf­fi­cient upon hatch­ing.

There is no pre-fer­til­iza­tion, pre-hatch­ing, or pre-in­de­pen­dence parental in­vest­ment ex­hib­ited by ei­ther par­ent in this species. There is also no post-hatch­ing or post-fledg­ing parental care, as the hatch­lings are fully formed and in­de­pen­dent at birth. ("Field Guide to North Amer­i­can rep­tiles and Am­phib­ians", 1997; Glos­sip and Losos, 2002)

• Parental Investment
• no parental involvement

Lifes­pan/Longevity

The lifes­pan of east­ern col­lared lizards varies de­pend­ing on fac­tors such as ge­net­ics, en­vi­ron­ment, and diet. In the wild, these lizards typ­i­cally have a shorter lifes­pan due to var­i­ous threats such as pre­da­tion, dis­ease, and habi­tat loss. In cap­tiv­ity, how­ever, they can live longer due to the avail­abil­ity of a con­sis­tent food source, vet­eri­nary care, and pro­tec­tion from preda­tors.

The typ­i­cal lower lifes­pan of east­ern col­lared lizards in the wild is around 2 to 3 years, while the typ­i­cal high­est lifes­pan is around 6 to 7 years. The av­er­age lifes­pan of this species in the wild is around 4to 5 years. In cap­tiv­ity, east­ern col­lared lizards can live up to 10 years or more with proper care.

Fac­tors that can limit the lifes­pan of east­ern col­lared lizards in­clude pre­da­tion, dis­ease, and en­vi­ron­men­tal stres­sors such as tem­per­a­ture ex­tremes and habi­tat loss. In cap­tiv­ity, a poor diet or im­proper hus­bandry prac­tices can also lead to health is­sues and a short­ened lifes­pan. ("COL­LARED LIZARD", 2023; "East­ern Col­lared Lizard", 2022; "Field Guide to North Amer­i­can rep­tiles and Am­phib­ians", 1997; J. E, 1992)

• Range lifespan
  Status: wild

  6 to 7 years

• Range lifespan
  Status: captivity

  10 to 15 years

• Typical lifespan
  Status: wild

  4 to 5 years

Be­hav­ior

Cro­ta­phy­tus col­laris is a soli­tary species that prefers to live alone. It is an ac­tive lizard and moves around fre­quently to find food and suit­able habi­tat. They are di­ur­nal while sleep­ing at night.

The east­ern col­lared lizard is known for its in­ter­est­ing be­hav­ior of doing push-ups to com­mu­ni­cate with other lizards and to at­tract mates. They also use their tails as a de­fen­sive mech­a­nism and can de­tach them if at­tacked by preda­tors.

Al­though they are soli­tary, east­ern col­lared lizards es­tab­lish and de­fend ter­ri­to­ries from other lizards of the same species. The so­cial hi­er­ar­chy is not well un­der­stood, but larger and more dom­i­nant in­di­vid­u­als may have an ad­van­tage in ac­quir­ing the best ter­ri­to­ries and re­sources.

Over­all, the east­ern col­lared lizard are a fas­ci­nat­ing species with in­ter­est­ing be­hav­iors such as ter­ri­to­ri­al­ity, push-up com­mu­ni­ca­tion, and tail de­fense. ("Adult male col­lared lizards, Cro­ta­phy­tus col­laris, in­crease ag­gres­sion to­wards dis­placed neigh­bours", 2003; "COL­LARED LIZARD", 2023; "East­ern Col­lared Lizard", 2022; "Field Guide to North Amer­i­can rep­tiles and Am­phib­ians", 1997; Glos­sip and Losos, 2002)

• Key Behaviors
• cursorial
• terricolous
• diurnal
• solitary
• territorial

• Range territory size

  2000 to 250000 m^2

Home Range

The home range of Cro­ta­phy­tus col­laris can vary de­pend­ing on fac­tors such as sex, age, and habi­tat qual­ity. Gen­er­ally, male east­ern col­lared lizards have larger home ranges than fe­males.

The home range of male C.​collaris can range from 1 to 25 hectares, while fe­male home ranges are smaller, rang­ing from 0.2 to 2 hectares. The size of the home range may also be in­flu­enced by habi­tat qual­ity and avail­abil­ity of re­sources, such as food and shel­ter.

East­ern col­lared Lizards de­fend their ter­ri­to­ries from other lizards of the same species and they may use cer­tain land­marks, such as rocks or trees, to mark their bound­aries.

Com­mu­ni­ca­tion and Per­cep­tion

One of the most no­table be­hav­iors is the use of push-ups to com­mu­ni­cate with other lizards and to at­tract mates. Males per­form push-ups to es­tab­lish ter­ri­to­ries and to sig­nal their dom­i­nance over other males. Fe­males also use push-ups to sig­nal their re­cep­tive­ness to mat­ing.

East­ern col­lared lizards have well-de­vel­oped vi­sion, which is im­por­tant for lo­cat­ing prey, avoid­ing preda­tors, and de­tect­ing po­ten­tial mates. They are also able to per­ceive their en­vi­ron­ment through their sense of smell and can use scent mark­ing to com­mu­ni­cate with other lizards and to es­tab­lish ter­ri­to­ries.

While in­di­vid­u­als are soli­tary, they may com­mu­ni­cate with oth­ers through vi­sual dis­plays such as head bob­bing and tail wav­ing. These be­hav­iors can be used to es­tab­lish dom­i­nance or to com­mu­ni­cate ag­gres­sion.

Dur­ing courtship, po­ten­tial mates may en­gage in vi­sual dis­plays and body move­ments to com­mu­ni­cate their in­ter­est in mat­ing. Once a male and fe­male have paired up, they may en­gage in courtship rit­u­als, which can in­volve vi­sual dis­plays and phys­i­cal con­tact. ("Adult male col­lared lizards, Cro­ta­phy­tus col­laris, in­crease ag­gres­sion to­wards dis­placed neigh­bours", 2003; "Field Guide to North Amer­i­can rep­tiles and Am­phib­ians", 1997; J. E, 1992; Sloan, 1996; Timanus, 2001)

• Communication Channels
• visual
• chemical

• Other Communication Modes
• duets
• pheromones

• Perception Channels
• visual

Food Habits

Cro­ta­phy­tus col­laris is pri­mar­ily in­sec­tiv­o­rous, with a diet con­sist­ing mainly of in­sects such as grasshop­pers, crick­ets, and bee­tles. They may also con­sume small lizards, spi­ders, and oc­ca­sion­ally plant ma­te­r­ial.

East­ern col­lared lizards have spe­cial­ized teeth that are adapted for cap­tur­ing and con­sum­ing in­sects. They have sharp, pointed teeth in the front of their mouths and flat­ter teeth in the back for crush­ing the ex­oskele­tons of their prey. Their pow­er­ful jaws and neck mus­cles allow them to quickly cap­ture and sub­due their prey.

They may oc­ca­sion­ally con­sume small ver­te­brates such as other lizards. How­ever, this makes up only a small por­tion of their over­all diet. ("COL­LARED LIZARD", 2023; "Field Guide to North Amer­i­can rep­tiles and Am­phib­ians", 1997; " Weapon Per­for­mance, Not Size, De­ter­mines Mat­ing Suc­cess and Po­ten­tial Re­pro­duc­tive Out­put in the Col­lared Lizard (Cro­ta­phy­tus col­laris)", 2005)

• Primary Diet
• carnivore
  • insectivore

• Animal Foods
• reptiles
• insects
• terrestrial non-insect arthropods

Pre­da­tion

One of the most no­table adap­ta­tions of Cro­ta­phy­tus col­laris is their abil­ity to change color. When threat­ened, they can darken or lighten their skin color to blend in with their sur­round­ings, mak­ing it dif­fi­cult for preda­tors to spot them. They can also puff up their bod­ies to ap­pear larger, which can in­tim­i­date preda­tors.

An­other anti-preda­tor adap­ta­tion of this species is their tail, which are ca­pa­ble of tail au­to­tomy. This al­lows the lizard to es­cape, as the preda­tor will be left with just the tail, which will con­tinue to move and dis­tract the preda­tor.

East­ern col­lared Lizards also ex­hibit cer­tain be­hav­iors to avoid preda­tors. For ex­am­ple, they will run quickly to es­cape dan­ger and will often climb trees or rocks to evade preda­tors. They can also use their sharp claws to de­fend them­selves if nec­es­sary.

Some of the known preda­tors of east­ern col­lared lizards in­clude birds of prey, snakes, and mam­mals such as coy­otes and foxes. Preda­tors can vary de­pend­ing on the lizard's life stage. Ju­ve­nile lizards are more vul­ner­a­ble to pre­da­tion than adults, and they often face dif­fer­ent preda­tors. For ex­am­ple, birds of prey and snakes are more likely to prey on ju­ve­nile lizards, while adult lizards are more likely to face mam­malian preda­tors. ("Adult male col­lared lizards, Cro­ta­phy­tus col­laris, in­crease ag­gres­sion to­wards dis­placed neigh­bours", 2003; "COL­LARED LIZARD", 2023; "Field Guide to North Amer­i­can rep­tiles and Am­phib­ians", 1997; Sloan, 1996)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • Red-tailed Hawk (Buteo jamaicensis)
  • Cooper's Hawk (Accipiter cooperii)
  • American Kestrel (Falco sparverius)
  • Coachwhip Snake (Masticophis flagellum)
  • Eastern Racer (Coluber constrictor)
  • Copperhead Snake (Agkistrodon contortrix)
  • Coyotes (Canis latrans)
  • Foxes (Vulpes spp)
  • Bobcats ("Lynx rufus")

Ecosys­tem Roles

As a preda­tor of small in­sects, east­ern col­lared lizards (Cro­ta­phy­tus col­laris) play an im­por­tant role in con­trol­ling in­sect pop­u­la­tions within their ecosys­tem. By con­sum­ing a va­ri­ety of in­sects such as crick­ets, grasshop­pers, and bee­tles, they help to main­tain the bal­ance be­tween preda­tor and prey pop­u­la­tions.

East­ern col­lared lizards may also have a role in seed dis­per­sal through their diet. Some in­sects they con­sume, such as grasshop­pers, can feed on plants and carry plant seeds in their di­ges­tive tracts. By con­sum­ing these in­sects, lizards can dis­perse plant seeds across their habi­tat, con­tribut­ing to the plant com­mu­nity's di­ver­sity and dis­tri­b­u­tion. (Clark, 2002; "East­ern Col­lared Lizard", 2022; "Field Guide to North Amer­i­can rep­tiles and Am­phib­ians", 1997)

• Ecosystem Impact
• disperses seeds

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

East­ern col­lared lizards do not pro­vide any di­rect ben­e­fits to hu­mans. How­ever, as a preda­tor of in­sects, they may help con­trol in­sect pop­u­la­tions in their ecosys­tem, which can in­di­rectly ben­e­fit hu­mans. In­sects can be pests that dam­age crops or spread dis­ease, and by con­trol­ling their pop­u­la­tions, east­ern col­lared lizards can help re­duce these neg­a­tive im­pacts. ("COL­LARED LIZARD", 2023; "East­ern Col­lared Lizard", 2022)

• Positive Impacts
• controls pest population

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known ad­verse ef­fects of Cro­ta­phy­tus col­laris on hu­mans

Con­ser­va­tion Sta­tus

East­ern col­lared lizards are cur­rently clas­si­fied as a species of Least Con­cern on the IUCN Red List, which in­di­cates that it is not con­sid­ered at sig­nif­i­cant risk of ex­tinc­tion. Con­ser­va­tion ef­forts for east­ern col­lard lizards in­clude habi­tat pro­tec­tion and restora­tion, as well as reg­u­la­tions on col­lect­ing and trade. ("East­ern Col­lared Lizard", 2022)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Con­trib­u­tors

Ad­di­son Vande Plasse (au­thor), Col­orado State Uni­ver­sity, Tanya Dewey (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

2005.

Weapon Per­for­mance, Not Size, De­ter­mines Mat­ing Suc­cess and Po­ten­tial Re­pro­duc­tive Out­put in the Col­lared Lizard (Cro­ta­phy­tus col­laris)

1997. Field Guide to North Amer­i­can rep­tiles and Am­phib­ians. New York: Knopf.

2003. Adult male col­lared lizards, Cro­ta­phy­tus col­laris, in­crease ag­gres­sion to­wards dis­placed neigh­bours. An­i­mal Be­hav­iour, 65: 391-396. Ac­cessed Feb­ru­ary 10, 2023 at https://​doi.​org/​10.​1006/​anbe.​2003.​2058.

2023. "COL­LARED LIZARD" (On-line). INHS Her­petol­ogy Col­lec­tion. Ac­cessed Feb­ru­ary 10, 2023 at https://​herpetology.​inhs.​illinois.​edu/​species-lists/​ilspecies/​collared-lizard/​.

2022. "East­ern Col­lared Lizard" (On-line). Mis­souri De­part­ment of Con­ser­va­tion. Ac­cessed Feb­ru­ary 10, 2023 at https://​mdc.​mo.​gov/​discover-nature/​field-guide/​eastern-collared-lizard.

Clark, D. 2002. Sex­ual dichro­ma­tism and dif­fer­en­tial con­spic­u­ous­ness in two pop­u­la­tions of the com­mon col­lared lizard (Cro­ta­phy­tus col­laris) from Utah and New Mex­ico, USA. Bi­o­log­i­cal Jour­nal of the Lin­nean So­ci­ety, 77: 67–85. Ac­cessed Feb­ru­ary 10, 2023 at https://​doi.​org/​10.​1046/​j.​1095-8312.​2002.​00092.​x.

Glos­sip, D., J. Losos. 2002.

Mi­cro­hab­i­tat Use and Ther­mal Bi­ol­ogy of the Col­lared Lizard (Cro­ta­phy­tus col­laris col­laris) and the Fence Lizard (Scelo­porus un­du­la­tus hy­acinthi­nus) in Mis­souri Glades

J. E, B. 1992. Size and Growth Rate Char­ac­ter­is­tics of a Pe­riph­eral Pop­u­la­tion of Cro­ta­phy­tus col­laris (Sauria: Cro­ta­phyti­dae). Copeia, 1997: 968-980. Ac­cessed Feb­ru­ary 10, 2023 at https://​doi.​org/​10.​2307/​1446626.

Sloan, C. 1996. Age and Gen­der-Re­lated Dif­fer­ences in the So­cial Be­hav­ior and Mat­ing Suc­cess of Free-Liv­ing Col­lared Lizards, Cro­ta­phy­tus col­laris. Copeia, 2: 336-337. Ac­cessed Feb­ru­ary 10, 2023 at https://​doi.​org/​10.​2307/​1446849.

Timanus, D. 2001. In­tra- and In­ter-sea­sonal Vari­a­tion in the So­cio-Spa­tial Be­hav­ior of Adult Male Col­lared Lizards, Cro­ta­phy­tus col­laris (Rep­tilia, Cro­ta­phyti­dae). Ethol­ogy, 107: 15-32. Ac­cessed Feb­ru­ary 10, 2023 at https://​doi.​org/​10.​1046/​j.​1439-0310.​2001.​00628.​x.