There are roughly 340 species of hummingbirds, belonging in the family Trochilidae. Their name came about because of the humming sound made from the rapid beats of their wings. Hummingbirds are native only to the Americas, with most species residing in Central and South America.
One of the many interesting facts about hummingbirds is their small sizes, considering the remarkable abilities they possess. The average hummingbird weighs about 0.106 ounces and has a length of 3.5-4 inches. The smallest hummingbird (and the smallest bird in the world) is the bee hummingbird, weighing about 0.06 ounces and measuring about 2 inches. The largest is roughly 0.85 ounces in weight and 8.5 inches in length.
The hummingbird can flap its wings at a rate of 8-90 beats per second, with the smallest species having the highest rates. Their heart rate is also incredibly fast, reaching as high as 1,260 beats per minute (an average human's heart rate ranges between 60-100 beats per minute). Most organisms that have very rapid metabolisms live a short life. The average life span of a hummingbird is 3-4 years. Many die during their first year and the longest recorded one to survive is 12 years.
Hummingbirds can fly at speeds exceeding 34 mph. They can hover in mid-air, fly vertically, laterally, and are the only group of birds that can fly backwards. Because flying requires much energy, they spend most of their day sitting or perching. During the night, hummingbirds go into a hibernation-like state (torpor) and their heart rate decreases dramatically, about 50-180 beats per minute.