What do ungulate animals alone have

Hooves
Ungulates (pronounced /ˈʌŋɡjᵿleɪts/) are any members of a diverse clade of primarily large mammals that includes odd-toed ungulates such as horses and rhinoceroses, and even-toed ungulates such as cattle, pigs, giraffes, camels, deer, and hippopotamuses.

Most terrestrial ungulates use the tips of their toes, usually hoofed, to sustain their whole body weight while moving. The term means, roughly, "being hoofed" or "hoofed animal".

As a descriptive term, "ungulate" normally excludes cetaceans (whales, dolphins, porpoises), as they do not possess most of the typical morphological characteristics of ungulates, but recent discoveries indicate that they are descended from early artiodactyls.

Ungulates are typically herbivorous (though some species are omnivorous, such as pigs), and many employ specialized gut bacteria to allow them to digest cellulose, as in the case of ruminants.

They inhabit a wide range of habitats, from jungles to plains to rivers.

Source: https://en.wikipedia.org/wiki/Ungulate