Answer:
The pygmy shrew
Explanation:
The pygmy shrew, which weighs in at less than an ounce, has the fastest heartbeat of any mammal at 1,200 beats per minute, according to the National Wildlife Federation.
I believe that would be the Hummingbird. Their hearts can be as fast as 1260 beats per minute. This is typically attained while they are hovering.
When they are just flying, their heart beats approximately 800 beats per minute.
When they are perched on a branch, it drops to around 400 beats per minute.
A lot of people wonder how a Hummingbird can make it through the night without eating, and that's a very good question. They normally have to eat every 15 minutes during the day, and they use their vision to find food including bugs that they snatch right out of the air.
Each night they go into a type of semi-hibernation called Torpor. Their energy consumption drops almost 90%, and their heart beats as low as 40 beats per minute. While they are in this state they are very vulnerable to predators such as tree snakes or anything else that can get to them. It takes them about 30 minutes to reverse this process so they can fly off in the morning and start the eating process all over.
