Here is the full list of all 31 Tamarin achievements.
Do a handstand
Save brother tamarin
Cut a birdcage rope
Break into caves
Break into a house
Defeat a molebug
Collect an invincibility flower
Defeat a damselfly
Collect 50 insect tokens
Save female tamarin
Defeat 100 ants
Defeat a beetle
5 ant headshots in a row
Open a firefly door
Platinum Trophy
Collect 6 pinecones
Defeat a snake
Do a turnjump
Collect all blackccurrants
Save baby tamarin
Find all memoirs
Purchase all weapons
Defeat 200 airborne enemies
Defeat 100 groundbugs
Full sap capacity
Upgrade to maximum capacity
Rescue all birds
Collect all currants in Eyja Mountain
Collect all currants in Lyngna Fjord
Collect all currants in Fraena Forest
Collect all fireflies