A (23) | B (24) | C (45) | D (19) | E (25) | F (18) | G (15) | H (14) | I (14) | J (2) | K (3) | L (9) | M (15) | N (11) | O (10) | P (34) | Q (3) | R (22) | S (30) | T (14) | U (3) | V (9) | W (7) | Z (2)

A means by which bats and certain other animals can find their way, find food, or avoid obstacles by emitting a series of sounds, often inaudible to humans, which echo back from an object and are received by the ear.


The study of animals, plants, and their environment (the world around them).


All living things depending on one another to survive in a certain area.


Ecologically sensitive travel that combines the pleasures of discovering and understanding flora and fauna with opportunities to contribute to their protection.


A cold-blooded animal; that is, an animal whose body temperature varies with the temperature of its surroundings. Ectotherms cannot produce their own body heat./To be an ectotherm.

Egg tooth

A hard, sharp prominence on the tip of the beak of baby birds and reptiles with which they break through the eggshell.

Emergent layer

Widely scattered tall trees that break through the canopy of a tropical rain forest.


A space in a zoo where animals live and are cared for.


Animals or plants that survive in such low numbers that they could become extinct in a few years unless something is done to help the populations increase.


A warm-blooded animal; that is, an animal that maintains its body temperature at a relatively constant level regardless of the temperature of the environment.


Enrichment is an important part of animal care. It is made up of the many ways in which keepers provide zoo animals with opportunities to do something with their time, giving the animal mental stimulation and physical exercise. Enrichment also gives animals choices and some control over their environment.


Everything that surrounds an animal or other living thing. For example, a pond is a frog's environment.

Environmental indicator species

An animal or plant that is monitored to determine the health of an entire ecosystem.


Soil being washed away, usually by wind or water and after vegetation has been removed.


A sleepy or dormant state caused by hot, dry, summer conditions.

Estrus (cycle)

The rhythmic changes in the mammalian female that enable her to become pregnant.


An exact catalog of all behavior patterns occurring in a species, including the vocal patterns.


The science and study of animal behavior.


Liquid water turning into gas vapor.


A very slow growth or change.

Ex situ

In captivity.


Meaning <i>outside skeleton,</i> it refers to certain animals' hard outer bodies. For example, many insects have a hard skin called an exoskeleton. The exoskeleton does not grow; it must be molted. Crabs, lobsters, and tarantulas have exoskeletons, too.


Foreign to a particular place, from another part of the world; not indigenous.


No longer existing. For example, dinosaurs are extinct./The process of becoming extinct.


Refers to a species that is extinct in a certain area. For example, the elk was extirpated from Wisconsin in the late 1800s.