|Twins born to a manatee under human care at Zoo Parc, France (http://www.zoobeauval.com/||)|
One of the reasons that manatees (Sirenia: Trichchidae) continue to be considered threatened and endangered, even in Florida where they are fully protected, is due to their very slow reproductive rate. Female manatees of the Florida subspecies (Trichechus manatus latirostris) mature around the age of four and if they are very successful mothers, they can give birth to a single calf once every 2-3 years.
Twins are rare and in many cases, one or both of the twins fail to survive. I've been observing manatees in the wild for over 13 years and have only encountered twins twice: once in Florida (on a rescue mission where both twins were stillborn and the mother died postpartum) and once in the Dominican Republic (both twins and the mother appeared to be healthy). In the DR case, we have no "proof" the dyads found associated with single adults in this study are twins, yet. But there are lines of evidence to support our hypothesis.
There are also documented cases of twins born to manatees under human care, for example, in facilities in Brazil (http://www4.icmbio.gov.br/cma//) and France (http://www.zoobeauval.com/ ).
Watch the video: http://www.youtube.com/watch?v=xgZJoNj2r60
So, this is indeed a rare and special event; the full story is here: