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Science & Medicine

Baby Anacondas Surprise Aquarium


The birth of some animals at an aquarium wouldn't normally be news. But the arrival of two baby anacondas took the staff of the New England Aquarium in Boston by surprise. Craig LeMoult of member station WGBH explains why.

CRAIG LEMOULT, BYLINE: Biologist Tori Babson takes care of all kinds of animals at the New England Aquarium and says things got especially interesting there late one afternoon in January.

TORI BABSON: I was cleaning up my tanks, getting everybody fed before the end of the day.

LEMOULT: And then she heard something weird.

BABSON: One of the event staff walked by the tank and noticed that there were a bunch of little babies in the exhibit.

LEMOULT: She went to check it out. And sure enough, there they were. Unlike most snake species, anacondas don't lay eggs. They have live births.

BABSON: So it looks pretty much like you would imagine, a tiny baby snake coming out of a bigger one.

LEMOULT: There were actually 18 babies, each about 2 feet long, emerging from a 30-pound, 10-foot-long anaconda named Anna.

BABSON: We were all quite surprised, definitely had no idea that we had a pregnant snake - equally surprised because there were no males in the exhibit. All four of the adults that are in there are all confirmed females.

LEMOULT: The mother anaconda had never encountered a male snake. She did this all on her own. Babson reaches into a terrarium and pulls one of the babies out.

BABSON: They have black spots all along their dorsal side. And their ventral side is more yellow and gray spots with a yellow line going down the middle.

LEMOULT: Reproduction without a male is not unheard of. Senior biologist Sarah Tempesta says it's called parthenogenesis.

SARAH TEMPESTA: Parthenogenesis is more common in plants and in invertebrates. So things like wasps, ants, aphids, you'll see parthenogenesis more frequently than you will in vertebrate species.

LEMOULT: But it does sometimes happen in things like lizards and snakes, especially if they're in captivity and kept apart from males. She says this is the second known case in green anacondas.

TEMPESTA: Some species simply clone themselves. So they duplicate their DNA, duplicate their cells. And all their offspring will be completely identical to themselves.

LEMOULT: Or sometimes unfertilized eggs can be fused with other cells from the mother that aren't normally used for reproduction. It took several months for the New England Aquarium to get DNA testing back on these snakes. And ultimately, they did confirm this was parthenogenesis. In fact, these babies do appear to be clones of their mom. If all that sounds familiar from somewhere, you might remember it was a plotline in the dinosaur movie "Jurassic Park."


BD WONG: (As Henry Wu) You're implying that a group composed entirely of female animals will breed?

JEFF GOLDBLUM: (As Dr. Ian Malcolm) No, I'm - I'm simply saying that life finds a way.

TEMPESTA: Yeah, so this is the same sort of concept. Life will find a way. These females, you know, in the absence of a male, have found another way to create offspring.

LEMOULT: The New England Aquarium recently confirmed what they believe is the first observed case of parthenogenesis in a small species of shark. But unfortunately, that offspring didn't survive. And of the 18 baby anacondas, 15 were stillborn and another died within a week. But two survived.

Is there any chance I could hold it?


LEMOULT: I could?

Tori Babson hands one over.

BABSON: So she may zoom around and try to - try to explore you a little bit.


BABSON: She also - if you can get one finger for her to anchor on - there you go.

LEMOULT: Oh, there you go.

It winds its way around my hands, sniffing at my wrists the way snakes do, by flicking out its little tongue. It's a bit awe-inspiring, actually, this odd and rare genetic marvel. And at this size, it's actually pretty cute. For NPR News, I'm Craig LeMoult in Boston. Transcript provided by NPR, Copyright NPR.