https://archive.ph/X3JL7 Primates in general seem to rarely give birth to twins, even though primates have two nuts: > DR. ROBERT M. YERKES has described the first authentic recorded case of the appearance of twins in an anthropoid ape family (Science, May 11, 1934). The twins, one male the other female, were born almost a year ago at the Anthropoid Experiment Station of Yale University, at Orange Park, Florida. The parents were chimpanzees, the male about eleven years old and the female about twenty. **Although among other primates, such as lemurs, gibbons, baboons and monkeys, twin births, according to Dr. Yerkes, have occasionally been recorded, the higher apes, chimpanzees, orang-outans and gorillas, have not hitherto been known to give birth to more than one young at a time**. If examined I think the *"two nuts, two children hypothesis"* would be proven invalid for most species.