How We Ended Up With an Invasive Species as a Pet

Our son's pet frog was a birthday gift about 15 years ago.

Blob, an African clawed frog
Blob in a quiet moment.

Mary Jo DiLonardo

Meet Blob.

He was a birthday present our son received way back in elementary school as part of a “grow a frog” kit. Luke graduated from college last year and is off to bigger and better adventures. Blob, however, is still with us.

After about 15 years, we’ve learned a lot about our unexpected, ridiculously hardy pet. He’s an African clawed frog who happens to be an invasive species. There’s an interesting story about how these amphibians ended up in the U.S. and they have a repertoire of fascinating quirky behaviors.

But first, Blob’s story.

The Grow-a-Frog kit included a tiny plastic aquarium, some itty-bitty pelleted food, and a gift certificate to mail away for a tadpole. Blob, I admit, was not the first arrival.

The first tadpole was Elliot, named after a contestant on the season of “American Idol” we were watching that year. But Elliot did not grow as he should and was found floating in the top of his mini-tank a few days after his arrival. We contacted the company and they quickly sent a replacement.

Like Elliot, he arrived rather unceremoniously in a bagful of water in a cardboard box. We set him free in his little home and Luke dutifully counted out a few pellets of food each day. Unlike Elliot, Blob thrived.

We visited the educational toy store by our home where they also had a Grow-a-Frog frog on display. This guy was beefy, lurking in the bottom of his tank. When we asked questions, inquiring about whether we should get our frog a pal, the store clerk strongly urged us to let him live solo. Their frog apparently had a death match with another frog and also mortally wounded some betta fish.

We were convinced Blob would forever live a solitary existence.

As Blob metamorphosed from a tadpole into a frog, we realized he needed better living quarters. A trip to the pet store resulted in a larger tank, some gravel, decorative greenery, and a bubble filter. Blob would have none of that.

He repeatedly attacked the filter, body-slamming it until it detached from the side of the tank. He dove into the gravel, sending it flying. Only the sturdier artificial plants and larger rocks survived his assaults.

Hardy, Quirky Frogs

Blob, we discovered eventually, is an African clawed frog or Xenopus laevis. They’re members of a highly aquatic frog family called pipids.

African clawed frogs were brought to the U.S. in the early 1900s. They became popular with researchers who found, among many things, that the frogs were useful for pregnancy testing. When they were injected with urine from a pregnant woman, the frogs were spurred to produce eggs.

The practice was continued through at least the 1960s when researchers found there were better ways to predict pregnancy. There was no need for these scientifically helpful creatures in the lab anymore.

“It was illegal to just dump them in the stream when you’re done with them,” Mark Mandica, founder and executive director of the Amphibian Foundation, tells Treehugger. “Back in the day I don't know if they were accidentally or intentionally released.”

But somehow African clawed frogs made it into the wilderness and now in the U.S. they are in at least two locations — Florida and California — where they didn’t normally exist.

“Even though they’re delightful and hilarious, they are negatively impacting the native wildlife. They do consume everything. They’re consuming native wildlife as well as competing with native wildlife. They’re pigs.”

Dinnertime with Blob is something else. He sometimes lurks in the bottom of his tank, coming up occasionally to get a gulp of air. Typically he spreads himself against the walls with his arms and legs spread wide.

When I open the lid to drop in pellets, he careens around the tank, splashing from wall to wall, near misses as he dives for the food or maybe just bounces around in glee that it's time to eat. 

When the pellets land in the water, Blob slams them into his mouth violently, using both his hands to shovel in the food.

“A typical frog will shoot its tongue out at food, but these frogs don’t have tongues,” Mandica explains. “Certain pipids use their hands differently. Blob and other clawed frogs use their hands quite comically. Others use their fingers to detect prey and don't quite stuff food in their mouths like that. That’s one aspect of how fascinating they are.”

Fascinating...but also somewhat violent, I point out. With the violent eating and the filter-attacking, I suggest to Mandica that Blob seems rather aggressive.

“I wouldn’t describe them as aggressive, but bombastic,” he counters. “Just bouncing off the thing until it breaks. These are ridiculous frogs. I’ve seen them on rainy nights in Miami crossing the streets.”

Life Expectancy and Singing

Mandica has about 15 African clawed frogs in a tank at his foundation. They mostly get along OK, but in the past sometimes they have gotten into a scuffle and occasionally someone hasn’t survived.

“If you put a clawed frog in there that is smaller than it is, it’s just going to eat it,” he says matter-of-factly. “If you feed it, they’re going to sometimes bite on each other thinking it’s food.”

There goes my idea of donating Blob, hoping he’d live a better life with fellow frogs. Guess he will stay with us forever which, apparently, might not be all that much longer.

“I think you have gotten Blob well past the normal life expectancy,” Mandica says, gently. “I think 99.9% of these frogs don’t get to be 15 years old.”

Which somehow makes me happy and sad for Blob.

We’ve been calling Blob a “he” all these years and I wondered if Mandica could tell us the frog’s sex based on photos or information about his behavior. When I told him that Blob loves to sing after his tank has been cleaned, he confirmed that Blob is indeed a guy.

“He’s calling to try to woo a female. He’s hopeful,” Mandica says. “The strategy is you sing the best song you can as a fella and you’re hoping that call attracts a female to you.”

He says often the calling begins in the water after a heavy rain which would freshen or change the water level. Cleaning the tank inspires Blob to renew his interest for a female friend. (You can listen to African clawed frog calls recorded in the lab at the University of California.)

Choosing a Pet Frog

Although Blob doesn’t provide love and snuggles like our dog or the puppies we foster, he played a part in making all of us appreciate nature. Through the years, my son marveled in Blob’s weirdness, captivated by his silly antics and his loud trilling. He may not have cleaned the tank or fed the frog as much as I did, but he learned about responsibility and love of animals.

I asked Mandica if he’d recommend that parents get pet frogs for their children.

“If I didn’t have a pet frog I wouldn’t be doing what I’m doing today. It was a pet frog that started me down this rabbit hole,” Mandica says. “My pet frog got sick, I met a frog guy at the university and he taught me about the field of herpetology. He had a cool lab with all this great stuff and it changed my life.”

Mandica, who now teaches amphibian biology at Agnes Scott College in Atlanta, has been focused on frogs ever since.

“It’s been exciting but also horrifying. The more I learn, the more I see amphibians are disappearing worldwide everywhere with 43% of the world's amphibians already documented as extinct.”

Getting a pet frog can be done sustainably and responsibly, he says, where you can find a frog that was captive-raised and not taken from the wild.

Just remember that it might be a 15-year commitment.