Wildebeest
Both species of wildebeest are even-toed, horned, greyish-brown ungulates resembling cattle. Males are larger than females and both have heavy forequarters compared to their hindquarters. They have broad muzzles, Roman noses, and shaggy manes and tails. The most striking morphological differences between the black and blue wildebeest are the orientation and curvature of their horns and the color of their coats. The blue wildebeest is the bigger of the two species. In males, blue wildebeest stand 150 cm tall at the shoulder and weigh around 250 kg, while the black wildebeest stands 111 to 120 cm tall and weighs about 180 kg. In females, blue wildebeest have a shoulder height of 135 cm and weigh 180 kg while black wildebeest females stand 108 cm at the shoulder and weigh 155 kg. The horns of blue wildebeest protrude to the side, then curve downwards before curving up back towards the skull, while the horns of the black wildebeest curve forward then downward before curving upwards at the tips. Blue wildebeest tend to be a dark grey color with stripes, but may have a bluish sheen. The black wildebeest has brown-coloured hair, with a mane that ranges in color from cream to black, and a cream-coloured tail. The blue wildebeest lives in a wide variety of habitats, including woodlands and grasslands, while the black wildebeest tends to reside exclusively in open grassland areas. In some areas, the blue wildebeest migrates over long distances in the winter, whereas the black wildebeest does not. The milk of the female black wildebeest contains a higher protein, lower fat, and lower lactose content than the milk of the blue wildebeest. Wildebeest can live more than 40 years, though their average lifespan is around 20 years.
Great bustard
The huge adult male great bustard is amongst the heaviest living flying animal. It is also arguably the most sexual dimorphic extant bird species, in terms of the size difference between males and females. Going on mass, the only known bird with a higher dimorphism is the green peafowl ("Pavo muticus") as the males are apparently near four times as heavy as the female. Among both bustards and all living birds, the upper reported mass of this species is rivaled by that of the kori bustard ("Ardeotis kori"), which, due to its relatively longer tarsi and tail, is both longer and taller on average and is less sexually dimorphic. In terms of weight ranges reported, the great Indian bustard ("Ardeotis nigriceps") also only lags slightly behind these species. A male is typically tall, with a length of around and has a wingspan. The male can range in weight from . Average male weights as reported have been fairly variable: in Russia, males weighed a median of ; in Spain, males weighed a mean of during breeding season and during non-breeding; in Germany, males weighed a mean of ; and the Guinness World Records has indicated that prior to their extirpation male bustards in Great Britain weighed an average of . Average weight of males is almost an exact match to that of male Kori bustards. Among all flying animals and land birds, male Andean condors ("Vultur gryphus") may match or exceed the mean body masses of these male bustards but not their maximum weights. Furthermore, male swans of the two largest species (trumpeter and mute) may attain a similar average mass depending on season and region. In a study in Spain, one male weighed as much as . The heaviest verified specimen, collected in Manchuria, was about . Larger specimens have been reported but remain unverified.