Copied my discussion verbatim from Discord:
I'd prefer a secondary weapon that is more akin to a tranquilizer, tracker, or scanner
Basically a bag & tag system
You tag the animal, research it, gain credits.
You can't bag & tag the same animal
Or you can choose to kill it and loot its corpse
The FarCry method of dealing with animals
To reiterate, you wouldn't take the animal with you, you'd tag it and research it over time.
Or you could kill it for a more immediate but less prosperous gain.
So you'd land on the planet, see a lifeform, shoot your secondary which tags it, take off, and research it in a separate menu with stats about the animal. You can do entire planets worth of animals or research a specific one, but the same animal over and over will generate decreasing returns so you'll have more incentive to tag new animals.
On the flip-side you can drop down and massacre an entire planet for a more immediate, but an overall less beneficial gain than long-term research.
I don't rightly know what kind of returns you can get from lifeforms, maybe a scientific credit system that lets you research more technology a la Kerbal Space Program.