This Teeny, Tiny Toadlet Will Never Land on its Feet

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Brachycephalus ephippium is the scientific name for a tiny South American amphibian species. They are, however, more affectionately known as pumpkin toadlets. These cute little creatures have been filmed trying to jump and leap like their larger frog and toad relatives but they don’t seem to be able to do it. The above video shows how they can take off quite normally but then flip over in mid-air and often land on their backs. It’s a highly inefficient and inaccurate way of moving around. So, here we will analyze why this happens and how a toadlet that is so bad at jumping can even survive!

Problems Associated With Being a Tiny Toadlet

Pumpkin toadlets are a type of shield toad, and they are very small! In fact, they are one of the smallest frogs/toads on Earth. Their body length is an average of just 0.7 inches. They are typically bright orange or yellow with tiny bumps on their back.

Miniaturization (becoming very small) is an adaption seen in several frog and toad species and it allows them to hide away in tiny spaces. However, it also has its disadvantages. Being miniaturized means that the parts of the body that were small to begin with are now ridiculously tiny and, as a result, stop working properly. This is what has happened to the vestibular system of pumpkin toadlets.

Pumpkin Toadlet Vestibular Systems

The vestibular system is the series of tiny bones and tubes in the inner ear that help vertebrates balance. The tubes, called canals, are filled with fluid and within them are sensory cells. This is how we ‘feel’ in which direction our head is turning and whether we are upside down or the right way up. For example, when toads take a leap into the air, the vestibular system tells the brain if their body is starting to rotate. The brain can then send signals to the muscles of the body to twist the torso and limbs around to make sure that the toad lands safely on their feet.

The problem is that these canals in the pumpkin toadlet’s vestibular system are so small that they do not work correctly. In fact, they are the smallest ever recorded for adult vertebrates. The quantity of fluid in the canals is so negligible that it cannot trigger the sensory cells to send a message to the toadlet’s brain telling it which way up it is. So, the toadlet’s brain thinks the jump is going great – right up until the moment it lands on its back. As you can see in the above clip, the toadlet starts to rotate around halfway through the leap. It makes no attempt to straighten out. In the second leap, it lands with enough momentum to roll back into an upright position. That is down to luck and has nothing to do with the vestibular system.

How Can Pumpkin Toads Survive Without Jumping?

A toadlet who is not very good at jumping, and who lands in a helpless position on their back, cannot travel very far and is very vulnerable. So how do they get around and how can they survive?

To answer this we first need to look at where they live and the dangers they may face. Pumpkin toadlets are a native species of the neotropical rainforests along the Atlantic coast of southeastern Brazil. They like warm and humid conditions and avoid open areas. Instead, they spend most of their time on leaf-covered forest floors and under logs and branches. So, they don’t move very far and can travel by simply crawling around rather than having to take huge jumps.

But what about predators? Many frog/toad species use their big leaps as a way of getting away from animals that want to eat them. Pumpkin toadlets are hunted by ground-foraging birds so they have had to develop other defensive strategies to make up for their lack of jumping finesse and accuracy.

Pumpkin Toadlet Defense Strategies

Firstly, their bright coloration is a warning to potential predators. It means “I am toxic so don’t eat me”. These little toadlets are indeed toxic. Their skin and liver contain high concentrations of tetrodotoxin. This is a neurotoxin that has no antidote. Also, they hide away amongst the leaf litter where predators are less likely to see them.

Finally, if a predator does spot them and is foolhardy enough to approach them, the little toadlet emits a high-pitched warning call. This puts the intruder off and warns other toadlets nearby that they need to hide. Male toadlets will also move their forearms up and down over one of their eyes which serves as an additional warning sign. When you are this toxic and scary, you don’t need to be able to jump!