Red kangaroo has the ability to freeze the development of an embryo until the previous joey is able to leave the pouch. This is known as diapause, and will occur in times of drought and in areas with poor food sources. The composition of the milk produced by the mother varies according to the needs of the joey. In addition, red kangaroo mothers may "have up to three generations of offspring simultaneously; a young-at-foot suckling from an elongated teat, a young in the pouch attached to a second teat and a blastula in arrested development in the uterus". The kangaroo has also
Wondiwoi tree-kangaroo in decline due to hunting pressures. Although the area has not been well-sampled, there have been a few visits to the area with no reports of this species." In 2018, a British amateur botanist photographed what is believed to be a living specimen of the Windiwoi tree-kangaroo in the mountains of New Guinea . The species status of Dendrolagus mayri is uncertain. Some authorities refer to all 'dorianus type' tree kangaroos as subspecies of Doria's tree kangaroo, including Colin Groves, who published a major revision of the taxonomy of the genus in 1982. More recent DNA analysis indicates, however, that