Scientists saved an endangered Puerto Rican toad by barking at it to make it pee

Olaf the Puerto Rican crested toad.
Olaf the Puerto Rican crested toad. Photo credit: Fort Worth Zoo

Scientists in the US are celebrating after successfully breeding an endangered toad from harvested semen.

Olaf - named after the frozen sperm he came from - is one of more than 300 Puerto Rican crested toads that have been hatched from semen collected by scientists.

Extracting semen from the toads is usually simple. It is released in their urine, and most toads will pee when they're picked up.

But for those that don't, scientists have figured out another trick.

"If you hold them in your hand and look at them and bark at them like a dog, they will pee," ectotherms curator of Texas's Fort Worth Zoo Diane Barber told Associated Press.

Barber was part of the group of scientists who travelled to Puerto Rico to collect the semen from six male toads which were later released back to the wild.

The semen was preserved in liquid nitrogen to be transported to the zoo so it could be used to impregnate the two female toads at Fort Worth.

To prepare the toads to reproduce, they are exposed to cooler temperatures and fake rain for three months, said Barber.

Of the more than 300 toads born, 100 will go to zoos with captive breeding programs.

The remaining 200 will be sent to their homeland of Puerto Rico to be released into the wild.