Vertebrate Zoology - V. M. Konstantinov 2011

Chordates
Terrestrial or Tetrapod Vertebrates — Amniotes
Class Birds — Subclass Fan-tailed Birds, or Modern Birds — Superorder Paleognathae, or Ratites — Order Cassowariformes, or Australian Ostriches

Australian ostriches are large, three-toed ratites with highly reduced, externally almost invisible wings, and legs that are relatively shorter than those of other ostriches. The HEAD is sparsely feathered, and the feathers feature aftershafts.

Representatives of the genus emu (Dromaius) are characterized by a uniform gray plumage and a relatively fully feathered Head and Neck (see Fig. 144). These birds reach a height of up to 170 cm and a mass of 37–55 kg. The species Dr. novaehollandiae inhabits the inland steppe-desert regions of Australia, living in small groups of 4–6 individuals. They are monogamous, but parental care is provided exclusively by the male, who builds the nest, incubates the eggs, and tends to the brood, keeping the female away from both the nest and the chicks. The clutch consists of 7–16 dark green eggs, with an incubation period averaging 52 days. The chicks are grayish with dark longitudinal stripes, reaching sexual maturity at two years of age. Their diet is predominantly plant-based. When properly kept, emus reproduce well in zoos, even in the temperate zone of European Russia. Adults tolerate frost relatively easily, whereas dampness, conversely, affects them adversely. Emus have been successfully bred in semi-captive conditions in southern Ukraine at the Askania-Nova Institute of Acclimatization and Hybridization.

The genus of cassowaries (Casuarius) comprises several species of large birds (height up to 170 cm, mass up to 80 kg) distributed across New Guinea and Australia. Cassowaries are distinguished by bare, brightly colored upper necks and heads, and a large keratinous casque on the head (see Fig. 144). Their overall coloration is black, with loose, Hair-like barbless feathers resembling long bristles. Unlike the steppe-dwelling emu, cassowaries inhabit dense tropical forests. They build their nests on the ground, laying a clutch of 3–5 green eggs weighing 600 g each. Incubation lasts 6–7 weeks and is undertaken by both parents or by the male alone; the male is solely responsible for caring for the brood. The diet of cassowaries is generally similar to that of emus.