Sealeo's hand-like sets of whiskers, used today to juggle pokeballs in aquariums and circuses, were developed to aid in the carrying of their young. Newborn Spheal are round and about the size of the pokeballs used today, so some have speculated Sealeo to simply be naturally adept at this. It is difficult to imagine a reason why they would juggle their young, but scattered sightings of them doing exactly that dot the historical record; like humans climbing trees, it has no more apparent purpose than to challenge one's self and see the world from a different angle.
Sealeo and their whiskers are also noted for the annoyance they pose to fishermen. The pokeball lures used by modern fishermen are round, yet a Sealeo's whiskers are too light to open it; instead, they use the lures to juggle, and do a remarkable job, shifting casually away from the efforts of fishermen to control their own lures until their would-be-captors gave up and went to some other part of the ocean. Sealeo are certainly a playful pokemon, but these taunts have another motivation; Sealeo prey on many of the same water pokemon that humans do. By simultaneously entertaining, challenging, and frustrating fishermen enough to make them go away, the Sealeo avoid being driven out as pests while protecting their next meals from overfishing.
Yet a pokeball is a pokeball, so every now and then a Sealeo slips up and the ball lands on its head, or they meet a fisherman with sufficient control to capture them – or in these days of scarcity in the oceans, are simply bribed out of the water by the promise of free fish. When this happens, they will gladly perform for audiences from their water tanks or ice rinks, provided they get their delicious reward.