Although the Eurasian beaver appears superficially similar to the North American beaver, there are several important differences, chief among these being that the North American beaver has 40 chromosomes, while the Eurasian beaver has 48. The two species are not genetically compatible: After more than 27 attempts in Russia to hybridize the two species, the result was one stillborn kit that was bred from the pairing of a male North American beaver and a female Eurasian beaver. The difference in chromosome count makes interspecific breeding unlikely in areas where the two species’ ranges overlap.[2]
https://en.wikipedia.org/wiki/Eurasian_beaver
#36. The Gene/DNA incompatibility between No. American and Euroasian beavers means that Rosie O’Donnell can never breed.
That’s a relief. No invasion of America by bucktoothed, fat, unfunny beavers who hate Trump.