What do animals breathe out that is poisonous to animals?

Animals, including humans, breathe out carbon dioxide (CO2). While CO2 is not poisonous in small amounts, high concentrations of it can be harmful and even deadly to animals.

Here's why:

* Displaces oxygen: CO2 displaces oxygen in the air, making it harder for animals to breathe.

* Acidifies blood: CO2 dissolves in the blood, forming carbonic acid, which can lead to acidosis. This disrupts the body's chemical balance and can damage organs.

* Suffocation: In very high concentrations, CO2 can cause suffocation.

However, animals typically breathe out CO2 in small amounts and are not harmed by it. It's important to note that the buildup of CO2 in enclosed spaces can be dangerous, as it can reach high concentrations and pose a risk to animals and humans.