The differences between a cobra and a rattlesnake include the type of venom they have and the fangs with which they inject it, their appearance, their distinctive characteristics and their deadliness to humans. Additionally, cobras and rattlesnakes live in different parts of the world.
Rattlesnakes are pit vipers. They have long fangs that remain folded against their palates when they are not being used. The venom of most species of rattlesnake is hemotoxic, which means it destroys tissue and causes necrosis, a type of cell injury, and coagulopathy, or destructive blood clotting. If rattlesnake bites are properly treated, they are rarely fatal to humans. Cobras have shorter fangs that do not fold back. Their venom is a neurotoxin, which means it attacks the nerves, causing the victim's breathing and heartbeat to stop. Although cobras do not usually bite humans, when they do, the bite is often fatal.
Rattlesnakes have the triangular heads of pit vipers, whereas cobras have more slender, rounded heads. The distinctive characteristic of rattlesnakes is the hollow segments of keratin on their tails, which make the rattling sound, whereas cobras are known for their ability to expand their neck ribs to form a hood. Rattlesnakes are found in both North and South America, but cobras are native to Africa, the Middle East and southern and southeast Asia.