According to the mythology book I’ve been reading, the rules of burying animals were quite complex in the ancient times in Finland. Everything had a soul, the passage of which was hampered by water in any form. Animals also reincarnated and came back as the animals they were if their skeletons were left intact and they were buried properly. This is why the animals the ancient people liked tended to be buried with care and the vile vermin not so much.
You can’t reincarnate without your bones,
Or if your body is next to Davy Jones.
A dispersed skeleton is just like water,
One can’t return after one’s slaughter.
The soul cannot pass through a river or a lake,
Be you a human, a bear or a drake.
That’s why, if you bury an eagle or a wolf,
Break their bones, bury them in a gulf,
These beasts of harm can’t harass you again,
When trodden into a mire. Oh but when,
You are digging a hole for a fox,
A reindeer, a bear or your favorite ox,
Arrange their bones like they are alive,
They will return and help you strive.