Final answer:
Estrogen is the hormone responsible for causing estrus, or the heat cycle in animals. It leads to changes in the female's body which make her receptive to mating.
Step-by-step explanation:
The hormone responsible for causing estrus, or the heat cycle in animals, is estrogen.
Estrogen is a female sex hormone that plays a critical role in the reproductive system. During the estrus cycle, estrogen levels rise, leading to changes in the female's body which make her receptive to mating.
For example, in mammals like dogs, cats, and cows, high levels of estrogen cause the vulva to swell and attract males. This signaling helps ensure successful reproduction.
Learn more about Estrus hormone