Although there is still much debate about the origins of lemurs on Madagascar, it is generally accepted that a single rafting event, similar to the one that brought New World monkeys to South America, occurred around 50–80 million years ago and allowed ancestral lemurs to cross the Mozambique Channel and colonize the island, which had already split from Africa (while it was joined to the Indian subcontinent), approximately 160 million years ago.
An exception, however, is the Trainer dressphere, featuring the game's main characters fighting alongside a dog, monkey and bird, the three animals befriended by the Japanese folk hero Momotarō in a traditional story.
Babakotia and Mesopropithecus not only shared the indriid dentition, but also the indriid-like skulls, providing evidence that sloth lemurs were most closely related to living indriids, with monkey lemurs as a sister group to both.
In 1936, Alice Carleton mistakenly associated postcranial remains of the Diademed Sifaka (Propithecus diadema) from Ampasambazimba with Mesopropithecus pithecoides and came to the false conclusion that its morphology was like that of a monkey.
In certain cases, subfossil lemurs, such as the sloth lemurs and koala lemurs, may have used leaves as an important fallback food, whereas other species, such as the monkey lemurs and the giant aye-aye, specialized on structurally defended resources, such as hard seeds and wood-boring insect larvae.
In the recently extinct monkey lemurs (Archaeolemuridae) and sloth lemurs (Palaeopropithecidae), the toothcomb was lost and the incisors and canines resumed a typical configuration in the front of the mouth.
Rockfowl have been known to kill the young of other rockfowl, while nest predation is carried out by cobras of the genus Naja, the Nile monitor, sun squirrels, Red-chested Goshawks, and Procolobus monkeys.
Rotavirus serotypes were first described in 1980, and in the following year, rotavirus from humans was first grown in cell cultures derived from monkey kidneys, by adding trypsin (an enzyme found in the duodenum of mammals and now known to be essential for rotavirus to replicate) to the culture medium.
Stem cell transplants are a recent research target, because stem cells are easy to manipulate and stem cells transplanted into the brains of rodents and monkeys have been found to survive and reduce behavioral abnormalities.