Bomb Detector Rats' Genitals Will Open And Close Several Times Through Their Lives

Their vaginas open late in life, and might not stay open for long.


Rachael Funnell


Rachael Funnell

Digital Content Producer

Rachael is a writer and digital content producer at IFLScience with a Zoology degree from the University of Southampton, UK, and a nose for novelty animal stories.

Digital Content Producer

bomb rat vagina

“They do what now?” – Female bomb-sniffing rat, 2023. Image credit: Rosa Jay /

A rat that can sniff out bombs has just revealed a new party trick, as research has discovered that the African pouched rat’s genitalia is constantly transforming throughout its adult life. The unusual approach to reproductive development sees the vagina open, then seal up only to open again later. Magic.

The southern African giant pouched rat (Cricetomys ansorgei) has been greatly celebrated, sometimes literally with medals, for its contribution to research both in medicine and bomb disposal. Now, it may help us answer questions about mammalian fertility thanks to its peculiar ever-changing junk.


Estrogens influence female rats to become patent, which is when the vaginal introitus opens. Typically this occurs before birth or before puberty, and it was previously thought that once it had happened, it stayed the same throughout adulthood. 

Well, not so, says the southern African giant pouched rat.

Not only do these rats’ vaginas remain sealed well into adulthood, but they can also undergo what researchers are describing as an “astounding reversible transformation.” Non-patent female rats will have a smaller uterus, which gets bigger when they become patent again.

It’s possible that the reversible transformation is in response to a dominant female giving chemical cues to the other nearby females that prevent them from mating. This would seem to be supported by senior author Alex Ophir, associate professor of psychology at Cornell University, who observed several female rats developing patency all at once after a dominant female in the colony died.


"You could interpret it as manipulation by one female to get other females to stop reproducing, and in effect, they'll often in these cases, start to contribute to the care of the dominant reproducing female," Ophir told the Cornell Chronicle.

Exactly why this happens isn’t yet clear, but finding out could not only teach us more about these talented rats, but also potentially provide insights into how to better manage human reproductive health. Furthermore, the working status of these rats means they are bred, but historically it hasn’t been very easy to do. Gaining a firmer understanding of their reproductive organs could make it easier to facilitate future generations of tiny life savers.

Don’t believe us? In 2022, the world lost a leading name in landmine detection and disposal as it was announced that Magawa passed away peacefully at the grand old age of eight years old. Magawa located over 100 landmines and other explosives during his career, and earned the PDSA Gold Medal – the highest award for gallantry an animal can receive – in 2020.

People trash talk rats a lot, but with transforming vaginas and bomb-sniffing sense, we think they’re neat. 


The study is published in Current Biology.


  • tag
  • animals,

  • genitals,

  • rats,

  • vagina,

  • African giant pouched rats,

  • bombs,

  • landmine detector