Black mambas are famous for being one of the most dangerous snakes on the planet. But does that fear hold true? Find out more below.

Characteristics
Contrary to what its name would suggest, black mambas are actually brownish in color, ranging from olive to greyish tones, with paler bellies. Similar to cottonmouths, when threatened a mamba will open its mouth to show the black lining as a warning signal.
Black mambas have coffin-shaped heads and are lithe, athletic snakes. According to National Geographic, they can grow to be 14 feet long (4.25 meters), though their average length is around 8 feet (2.4 m). These giants can live up to 11 years in the wild.
Just two drops of potent black mamba venom can kill a person. Black mambas have a neurotoxic venom, which shuts down the nervous system and paralyzes victims.
Habitat
Black mambas reside in South and East Africa’s savannas, rocky hills and open woodlands, according to the University of Michigan Museum of Zoology’s Animal Diversity Web (ADW). They like low, open spaces and enjoy sleeping in hollow trees, rock crevices, burrows, or empty termite mounds.
Habits
These speedy serpents can move faster than most people can run, a fact that partly explains why they are so feared. Viernum said, “Black mambas are one of the fastest species of snakes, reaching slithering speed up to 12 mph [19 kph].” This is undoubtedly fast, but still slower than the myths of them outrunning horses would suggest. Over longer distances, they average about 7 mph (11 kph).
They slither quickly in short bursts over level ground, and can zoom along with about one-third of their bodies off the ground and their heads proudly held high. The black mamba racing along with its head nearly 4 feet (1.2 m) in the air is a terrifying and amazing sight. However, according to National Geographic, black mambas use their incredible speed to escape threats, not to hunt.
When threatened with no perceived available escape, these snakes will raise their upper body off the ground to stand erect. Their front third of their bodies can rise 3 to 4 feet (0.9 to 1.2 m) off the ground. Then, they will spread their cobra-like neck flaps [and] gape their mouths to expose the black lining. This is a defensive posture aiming to scare away the threat. If black mambas need to attack to defend themselves, they will strike repeatedly, potentially deliver large doses of venom with each strike, and hiss loudly. Then, they’ll slither away as fast as possible.
Bite
Just two drops of potent black mamba venom can kill a human, according to South Africa’s Kruger National Park. “Like cobras and coral snakes, the venom of a black mamba contains neurotoxins,” Viernum told Live Science. She described the venom as “fast-acting.” It shuts down the nervous system and paralyzes victims, and without antivenom, the fatality rate from a black mamba bite is 100 percent. “Fatalities from black mamba bites have been documented to occur within as little as 20 minutes after injection,” said Viernum. “However, most known fatalities have occurred within 30 minutes to 3 hours or longer.”

It appears, yes, black mambas are indeed as frightening as their reputation holds them to be. They can race along faster than most humans can sprint, and their venom can kill in as little as 20 minutes.

Although most fatalities occur after three hours, the prospect of a snakebite that can kill even that quickly is still terrifying. But, as the information above says, the black mamba will always choose running away over biting when possible. This is because venomous snakes prefer to use their venom on their prey, which is one thing we will never be, so no worries.

To learn more about the black mamba, check out Live Science.