Smallest known vertebrate (flea toad)

What to remember

In Brazil lives a flea toad, Brachycephalus pulex, whose adults can measure just 6.45 millimetres (0.254 in) from snout to vent. That minimum adult length makes it both the smallest amphibian and the smallest vertebrate known.

The measure used is the smallest adult, not the species' maximum size.

As with any claim about the smallest organisms, caution is in order: size can be judged in several ways, and knowledge of life is incomplete, so the smallest organism may not have been discovered yet.