Hamster humour

It's a scientific fact that hamsters emit a rare pheromone called Oxydihorrian that is chemically similar to Nitrus-Oxide, or laughing gas.
In the late 1800's dentists actually used hamsters to help people deal with the pain of oral surgery because of these rare properties, but this was eventually phased out due to hygeine concerns.
You may also find yourself giggling around whales should you ever encounter one close up, as they emit the same pheromone. It's terribly ineffective under water, however.