Puffins

[Kkell93]

 

Adding Puffins to the game as small tames or shoulder mounts would be very useful in snow biomes due because of their ability to radiate heat into the air. Puffins large beaks function like radiators allowing them to quickly dissipate excess heat into the air. 

Puffins could also have a weight reduction on natural resources, or could be used as a method to harvest nearby fish without a fishing pole. 

https://journals.biologists.com/jeb/article/222/21/jeb216739/224504/Tufted-puffin-beaks-are-impressive-radiators

[Dienstbier]

Well, for the warmth we already have three animals. 
A: the otter as shoulder animal,
B: the Kairuku (no idea if you can carry it),
or 
😄 the Dimetrodon as a walking animal

The Hesperornis can kill and harvest super fish, the Otter is not the great hunter alone, but the Ichty is also a very good fish hunter.

Use the animals what we have than always new animals to add the prinziep the same can.