Which animals milk is the only that doesnt curdle when boiled?

That statement is incorrect! There's no animal milk that doesn't curdle when boiled.

Here's why:

* Milk curdles due to the protein structure: Milk contains proteins, primarily casein. When heated, these proteins denature (change shape), causing them to clump together. This clumping is what we see as curdling.

* All milk contains casein: While the amount and types of casein can vary between species, all milk contains casein, which will curdle upon heating.

So, the statement is a misconception.