Glossary: U

ulna

One of the two distal bones in the forelimb of tetrapods. Synapomorphy of tetrapods+Euthenopteron

ultrasound

uses sound above the range of human hearing for either navigation or communication or both

understory

The layer of shrubs, herbs and small trees beneath the forest canopy.

ungulate

A hoofed mammal which is usually adapted for running. Includes deer, cattle, gazelles, horses, elephants, and hyraxes. Most are large herbivores. The term no longer has taxonomic significance.

urban

living in cities and large towns, landscapes dominated by human structures and activity.