He arranged with the Primate Center of Rio de Janeiro to begin trials of different doses of yellow fever vaccines on about 60 monkeys, close relatives of the tamarins, in January 2018.

Source: https://gorgenewscenter.com/2023/02/01/race-to-vaccinate-rare-wild-monkeys-gives-hope-for-survival/

“It is normal for cotton-headed tamarins to give birth to twins every year in the wild but triplets are incredibly uncommon.

Source: https://www.alloaadvertiser.com/news/national/23543426.incredibly-rare-tamarin-triplets-born-marwell-zoo/?ref=rss

Older children could also offer certain advantages to their parents, Bales says, such as caring for their younger siblings, which happens to be the case for marmosets and tamarins.

Source: https://www.discovermagazine.com/planet-earth/just-like-us-animals-also-mooch-off-their-parents