Tooth-billed platypus

The **tooth-billed platypus** (*Microbunodon opidonta*) is a species of monotreme mammal, most closely related to the true platypuses and steropodonts such as *Steropodon*, that originally did not exist, but has since been created by SciiFii and introduced throughout the riverine ecosystems of South Australia to help boost biodiversity. The tooth-billed platypus is similar in size to the duck-billed platypus, varying from 0.7 to 2.4 kilograms (1 lbs 9 oz to 5 lbs 5 oz), with males being larger than females. Males average 50 centimeters (20 inches) in total length, while females average 43 centimeters (17 inches). Its lower jaw is complete with three lower molar teeth with well-developed, V-shaped transverse ridges, simpler in form than the molars of toothed platypuses but otherwise similar. As a result of having strong teeth, the tooth-billed platypus is capable of hunting for aquatic insects, crustaceans, annelid worms, small fish, and small frogs. The tooth-billed platypus is generally regarded as nocturnal and crepuscular, but individuals are also active during the day, particularly when the sky is overcast. The tooth-billed platypus is an excellent swimmer and spends much of its time in the water foraging for food. It has a very characteristic swimming style and no external ears. Uniquely among mammals, it propels itself when swimming by an alternate rowing motion of the front feet; although all four feet of the tooth-billed platypus are webbed, the hind feet (which are held against the body) do not assist in propulsion, but are used for steering in combination with the tail. The species is endothermic, maintaining its body temperature at about 32 °C (90 °F), lower than most mammals, even while foraging for hours in water below 5 °C (41 °F). The species exhibits a single breeding season; mating occurs between June and October, with some local variation taking place between different populations across its range. Observation, mark-and-recapture studies, and preliminary investigations of population genetics indicate the possibility of both resident and transient members of populations, and suggest a polygynous mating system. Females become sexually mature in their second year, with breeding still taking place in animals over eleven years old. Outside the mating season, the tooth-billed platypus lives in a simple ground burrow, the entrance of which is about 30 centimeters (12 inches) above the water level. After mating, the female constructs a deeper, more elaborate burrow up to 20 meters (65 feet) long and blocked at intervals with plugs (which may act as a safeguard against rising waters or predators, or as a method of regulating humidity and temperature). The male takes no part in caring for his young, and retreats to his year-long burrow. The female softens the ground in the burrow with dead, folded, wet leaves, and she fills the nest at the end of the tunnel with fallen leaves and reeds for bedding material. This material is dragged to the nest by tucking it underneath her curled tail. Newly hatched tooth-billed platypuses are vulnerable, blind, and hairless, and are fed by the mother's milk. Although possessing mammary glands, the tooth-billed platypus lacks teats. Instead, milk is released through pores in the skin. The milk pools in grooves on her abdomen, allowing the young to lap it up. After they hatch, the offspring are suckled for three to four months. During incubation and weaning, the mother initially leaves the burrow only for short periods, to forage. When doing so, she creates a number of thin soil plugs along the length of the burrow, possibly to protect the young from predators; pushing past these on her return forces water from her fur and allows the burrow to remain dry. After about five weeks, the mother begins to spend more time away from her young, and at around four months, the young emerge from the burrow. The conservation status of the tooth-billed platypus is **Least Concern** due to successful conservation efforts, the tooth-billed platypus's wide range and its tolerance to many of the human activities.