Swarms is the fifth episode of season two

  • Number 10 Mouse - it breeds fast thanks to nice weather and an abundance of food. Amount in a swarm: 10's to 1000's
  • Number 9 Grunion - hundreds of thousands of them come ashore to mate. Amount in a swarm: 100,000's
  • Number 8 Caribou - swarm all over the countryside with twice as many caribou as people in Alaska. Amount in a swarm: 500,000
  • Number 7 Bat - hard to find your own baby and hard to find good sanitation so they go out for a breathe of fresh air. Amount in a swarm: 20,000,000
  • Number 6 Red Crab - 500 people share Christmas Island with about 120 million red crabs that march out to sea to mate. Amount in a swarm: 60,000,000
  • Number 5 Jellyfish - every day, they mass together to swim from one side of the lake to the other. Amount in a swarm: Unspecified
  • Number 4 Monarch Butterfly - can be 20 thousand on a branch and 220 million in a swarm. Amount in a swarm: 220,000,000
  • Number 3 Locust - lack in size but make up for in sheer weight of numbers; A single swarm can contain 40 billion insects that threaten at least 20% of the planet. Amount in a swarm: 40,000,000,000
  • Number 2 Krill - stick together in a swarm to stay out of trouble; Can be up to 2 million tons of krill; There are 100,000 krill for every single human. Amount in a swarm: about 900,000,000,000
  • Number 1 Argentine Ant - form a super swarm to conquer the world by cooperating with each other. Amount in a swarm: 1,000,000,000,000's