#4 Poison Dart Frog

The vibrant colors may attract your attention, but they are also nature’s way of warning you to keep away. The poison dart frog is one of the most lethal animals on the planet. For instance, the two-inch golden poison dart frog carries enough toxin to kill ten adult people.

When a frog is consumed by a predator, its toxin targets the nervous system and can result in muscle spasms, salivation, and even death.

The cause of the frog’s toxicity is unknown to scientists, but they believe that this little killer may have picked up plant poisons via the ants, beetles, and other insects they consume. When grown in captivity and kept separate from local insects, poison dart frogs do not produce venom.