Question

What happens to animals that are deprived of oxygen

Answer 1

When animals are deprived of oxygen they die. 

Explanation;
Oxygen is an important gas in any animal's life. Animals need it to survive. 
Oxygen is required mainly for the process of cellular respiration, a process which plants use to generate energy that is required by the cells to carry out basic functions such as growth and movement. Without these basic  functions animals can not survive. Therefore; when animals are deprived of oxygen, they may utilize nutrients through anaerobic (without oxygen) respiration, after which they will eventually die. 

Answer 2

Brain damage caused from a lack of oxygen is called anoxic damage, while hypoxia describes a low-oxygen condition. In other words, someone suffering from a lack of oxygen is said to be hypoxic, but any damage sustained is anoxic damage.