Reptile Biology Glossary
22 key reptile biology terms — autotomy, ectotherm, parthenogenesis, temperature-dependent sex determination and more — used across GeckoDaily's classroom fact sheets and worksheets.
Autotomy
The ability to voluntarily detach a body part — in geckos, the tail — usually to escape a predator's grip. From Greek for 'self' + 'cutting'.
Cathemeral
Active at irregular intervals across both day and night, rather than strictly diurnal or nocturnal.
Clutch
A group of eggs laid by a female at one time.
Cloaca
The single posterior opening used for excretion and reproduction in reptiles (and birds, amphibians, and fish).
Diurnal
Active mainly during daylight hours.
Ectotherm
An animal that regulates its body temperature mainly through external sources of heat (such as sunlight) rather than generating heat internally. Often called 'cold-blooded', though body temperature can be quite warm when basking.
Endotherm
An animal that generates and regulates most of its own body heat internally, such as mammals and birds. Contrast with ectotherm.
Gravid
The reptile equivalent of 'pregnant' — carrying developing eggs.
Heliothermic
Regulating body temperature primarily by basking in direct sunlight.
Herpetology
The scientific study of reptiles and amphibians.
Incubation
The period during which an egg develops before hatching.
IUCN Red List
A global inventory maintained by the International Union for Conservation of Nature that assesses the extinction risk of species, using categories such as Least Concern, Vulnerable, Endangered, and Critically Endangered.
Morph
A distinct colour or pattern variation within a species, especially common in captive-bred reptile lines.
Nocturnal
Active mainly at night.
Oviparous
Reproducing by laying eggs that develop and hatch outside the mother's body.
Parthenogenesis
A form of reproduction in which an egg develops into an offspring without being fertilised by a male — producing genetic clones of the mother. Found in some reptiles, insects, and other invertebrates, but rare among vertebrates.
Setae
Microscopic hair-like structures on the toe pads of many geckos that allow them to grip smooth surfaces using weak intermolecular (van der Waals) forces.
Snout-vent length (SVL)
The standard way herpetologists measure a reptile's body: from the tip of the snout to the cloacal opening, excluding the tail. Used because tails are easily lost or regrown at different lengths.
Squamate
A member of Squamata, the reptile order that includes lizards and snakes — the largest order of living reptiles.
Temperature-dependent sex determination (TSD)
A reproductive system in which the temperature at which eggs are incubated — rather than sex chromosomes alone — influences whether offspring develop as male or female.
Thermoregulation
The set of behaviours and physiological processes an animal uses to keep its body temperature within a workable range.
Vulnerable (IUCN)
An IUCN Red List category indicating a species is considered to face a high risk of extinction in the wild, one step below Endangered.
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