Similarities and differences: impala vs springbok

The two commonest antelopes in southern Africa are the impala (Aepyceros melampus) and the springbok (Antidorcas marsupialis). Here are some similarities and differences perhaps new to readers.

In flight from predators, both bound high into the air even where there are no obstacles, while being perversely reluctant to jump over fences (instead preferring to crawl under them). However, the impala differs from the springbok in that it neither stands on its hind legs to reach food nor habitually uses a trotting gait.

Both have complex tails with two tracts of erectile fur, unlike any other ungulate. However, in the impala the piloerections are to the side and inwards (ventral), whereas in the springbok the piloerections are outwards (dorsal).

Both have one infant at a time and form creches. However, the impala has a flesh-coloured udder with four teats whereas the springbok has a black-pigmented udder with two. And the hiding period of infants is shorter in the impala than in the springbok, which is the opposite of expectations given that the impala is the more cover-dependent of the two species.

Both use urine and faeces for social communication, with similar postures. However, of the two species the territorial male piles his feces only in the impala.

Both are exceptionally noisy for antelopes in masculine display despite the normal appearance of the larynx; and both can utter their loudest calls while running after rival males (in contrast to deer which roar, bellow or grunt only while standing or walking). However, only the impala intersperses its rutting vocalisations with alarm-snorts.

Both have patterns of colouration similar to gazelles. However, that of the impala has a mainly camouflaging effect (see https://www.inaturalist.org/observations/78256383 and https://www.inaturalist.org/observations/77839882 and https://www.inaturalist.org/observations/75215507 and https://www.inaturalist.org/observations/67019115), which is odd for a species in which even infants are gregarious. By contrast the colouration of the springbok is more conspicuous (see https://www.inaturalist.org/observations/47788993 and https://www.inaturalist.org/observations/43308762 and https://www.inaturalist.org/observations/40749849 and https://www.inaturalist.org/observations/37893316 and https://www.inaturalist.org/observations/37480920) than any species of Gazella.

Both stot in earnest seemingly only for the painted hunting dog (Lycaon pictus). Both the kick-stotting of the impala and the head-down bouncing of the springbok are styles unique to these species. However, only in the springbok is the same stotting display also performed by the female in courtship.

Publicado por milewski milewski, 08 de mayo de 2021

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