Similarly to The Last of Us, it seems many members of the Resistance do not know how to swim, unless specifically trained to learn (Otter, Porpoise, and to a lesser extent Cheetah). This makes sense given that they mostly live underground in sewers. Could also fall into Crippling Overspecialization because only the members trained to swim know how to, while the other members don't.
The Animal Theme Naming reveals different attributes and abilities of the Resistance members:
Tiger, Wolf and Dingo are soldiers
Owl, The Smart Guy, is the leader or at least the planner.
Otter, Porpoise, and Cheetah are the aquatic members.
Mongoose and Cobra apparently never got along.
Initial impressions of Josh makes him out to be a cowardly wimp who avoids conflicts because he will lose. The further into the series we go, he continually tries to go for a diplomatic solution and not kill or maim anyone if possible. It seems to shift him into Technical Pacifist territory... and then you meet his parents and see the effect they have on Wolf and Tiger. These are the most supportive, kind people you might ever meet. Sure outwardly they seem like dweeby push-overs, but they tend to pull out of people their best inner selves. Josh doesn't wish to fight or kill anyone, always seeking a better solution to this gigantic, world-ending problem, because that's how he was raised.
In Season 2, Stu mentions all animals went extinct at least over 100 years. This explains why NAG citizens of this era, who were members of the Resistance in the old timeline, don't use animal code names. They would not have known about them in the first place.
