Over Half of Male Marmosets Carry Brother,Aeos Sperm

Gandalf of the Marmosets, Emperor Marmoset, Saguinus imperator

Animals that carry cells from another individual, most often a fraternal twin (non-identical), are known as chimeras. Aside from marmosets, chimeras have been discovered in humans, cats and cows. Considered a rare fluke in most species, marmosets have a unique embryonic development that results in most of them sharing chimeric blood. Researchers recently discovered that the swapping goes even further: 50% of male marmosets carry their brothers' sperm and 10% of female marmosets have their sisters' ovaries. That means marmosets can give birth to their own nephews and nieces! * insert Dueling Bangos theme here* Interestingly, mama marmosets seem to favor non-chimera offspring while fathers prefer the mixed offspring. This might be because the chimera offspring give off a wider variety of scents and are therefore more likely to smell like papa. Check out the NY Times article for more detail.

Adorable baby or huge, terrifying thumb?

Disco Fever. Pygmy Marmoset, Callithrix pygmaea