How to Sex Fire-Bellied Toads

Article and photos by Kimberly Halzen, 2025

How can you tell male vs female fire-bellied toads?

Here are some reference photos to compare! I have details below, but the easiest way to tell is to look at their front legs: if it looks like your toad has been hitting the gym, there's a good chance it's a boy. If it's been skipping arm day, it's probably a girl. Notable white freckles (pores) on the hands and forearms may also be a good indicator you have a boy.

When I first looked into this myself to double-check the sexes of our adult FBTs, I was pretty underwhelmed at the lack of resources and generally unhelpful descriptions, many of which cite very old and possibly inaccurate papers. You would think a species as well studied as Bombina orientalis would have some more definitive resources out there.

Behavior: Calling and Amplexus

Your best bet for identifying the sex of a toad [or more specifically identifying male toads] is by behavior. By the time juveniles are the size of a dime, some males are already calling and attempting amplexus (often on other males, who will eventually shake them off). If you observe calling or amplexus from an individual toad, that toad is male.

If you observe a toad allowing amplexus for extended periods of time (hours +), there is a good chance that is a female toad.

Male (left) grasps the female tightly around her waist in inguinal amplexus.

These adult toad photos cover only a single female, and four males. I look forward to having additional females in the future so I can compare traits over multiple individuals. I hate to draw conclusions from just one individual, but this is what we have to work with so far.

Visual Differences

I highly recommend moving each toad into a clear container individually and examining them with good lighting. If you can, take photos of each so you can more carefully compare them after the fact. Without good resolution photos to reference, I honestly would say our female doesn't really look different from our males. With photos, differences are a bit easier to pinpoint.

Adult Male	Adult Female
Behavior: May call or attempt amplexus.	Behavior: Will not call or attempt amplexus. May allow amplexus from male.
Forelimbs: More thick/defined forelimbs. Defined white pores on back of hands, may extend up arms and under chin. Nuptial pads difficult to see, but look like what you'd expect a clearish callus to look like, at the base of their first toe and an oval patch on the inner forearm. Short "thumb" (first toe).	Forelimbs: Thinner, smoother forelimbs. No well-defined, raised white pores. Base of "thumb" does not have a thickened pad. Toes overall a bit more slender, especially the first toe.

Female:

Males:

Traits that probably are not helpful for sexing:

• Overall Size: Many sources I found imply that females are generally larger than males. I have not found this to be the case with our group, and it does not seem to be true if comparing many documented wild male/female pairs in amplexus. I'd be interested to hear if you have a large female toad!

• Toe Webbing: Webbing on the back feet seems the same from what I can tell for both sexes. Sometimes it seems like the webbing connection varies, but it ends up just being the photo angle or how the foot is positioned.