The Suni is independent of drinking water, and gets its liquid intake from its food. Suni's lie in the shade of bushes or trees in the midday heat, and are perfectly camouflaged, but their twitching tails may give their presence away. They will freeze when disturbed, but will jump up at the last moment from their hiding place and bound away, usually with a characteristic backward glance once they have travelled some distance.
They are normally either solitary or in pairs, although they may be found in small family groups. The suni has a high pitched, barking cry which is used when danger is sensed; it can also emit a whistling snort. The male suni bleats like a goat when it pursues a female. Their single offspring is born during the summer months between August and February, and has a darker, deep reddish-brown coat. Lambs up to a week old hide, and their mothers visit them two or three times daily to suckle and clean them.