Millions of blue 'sailors' have washed up on US West Coast beaches, captivating people's attention. These creatures are actually a type of zooplankton called Velella velella. They have small, transparent sails that catch the wind, allowing them to drift across the ocean.

**What are these creatures?**
Velella velella is a type of zooplankton that lives on the surface of the ocean and moves with the wind. Their sails catch the wind, allowing them to drift across the ocean. These creatures are actually not a single animal, but a colony of many small organisms.

**The Direction of the Sails**
The sails of these creatures can be in different directions. About half have their sails open to the left, while the other half have their sails open to the right. This causes the wind to blow them to different parts of the ocean. However, in the spring, the wind direction changes, blowing from west to east. This causes large groups to wash up on beaches.

**Washing Up on Beaches**
These creatures wash up on beaches every spring. However, this year there are more of them. Scientists say that the warming of the ocean and a mild winter have caused their population to increase. The change in spring winds has caused these large groups to wash up on beaches.

**Effects**
These creatures are usually not harmful to humans. However, pets may experience stomach upset if they eat them. The main effect is the smell. These creatures can accumulate on beaches and give off a strong fishy smell. Luckily, the change in wind will cause them to disappear from the beaches.

**Did You Know?**
Velella velella lives on the surface of the ocean and moves with the wind. These creatures are actually not a single animal, but a colony of many small organisms. Each organism has a different function within the colony.

**Conclusion**
Millions of blue 'sailors' have washed up on US West Coast beaches, captivating people's attention. These creatures are actually a type of zooplankton called Velella velella. They live on the surface of the ocean and move with the wind, washing up on beaches and captivating people's attention every spring.