On 21 August 1986, a limnic eruption at Lake Nyos in northwestern Cameroon killed 1,746 people and 3,500 livestock.

Answer this question based on the passage: how many animals died in the lake nyos tragedy? Okie... think carefully first, then make a decision:
The relevant information is: On 21 August 1986, a limnic eruption at Lake Nyos in northwestern Cameroon killed 1,746 people and 3,500 livestock. So, the answer is 3,500.