Topic: Biology

Scientists from Stanford University found that fin whales can't filter-feed as fast when krill builds up on their baleen. They need a 15% clear area to expel water quickly.

Fin whales are huge creatures that feed on massive amounts of krill, which they filter through their baleen plates in their mouths. But researchers from Stanford University discovered that this process can be slowed down if too much krill builds up on the baleen.

The team, led by Ingrid Ackermann, calculated that a layer of krill 6.3 centimeters deep would clog the baleen and slow down the whale's ability to expel water. They found that hungry fin whales can expel water in just 31 seconds, but with a thick layer of krill, it would take them 16 minutes.

To test this, Ackermann and her team created a model using frozen krill and a tube to simulate the whale's mouth. They applied pressures ranging from 8.9 to 12.4 kilopascals (kPa) to see how fast water flowed through the krill. When they did this, the water speed plummeted to just 0.04 meters per second (m/s), which is much slower than the 0.67 m/s needed for the whale to empty its mouth quickly.

The researchers also found that if the whales can maintain a 15% clear area on their baleen, they can continue to filter-feed at their normal speed.

Why It Matters

This discovery is important because it helps us understand how fin whales adapt to their environment and find food. It also shows us how delicate their feeding process is and how much depends on the balance between water flow and krill buildup.

Key Facts

• Fin whales can filter-feed at a rate of up to 144 kg of krill per mouthful.
• The baleen plates in fin whales' mouths are like giant strainers that let water through while keeping krill out.
• A layer of krill just 6.3 centimeters deep on the baleen can slow down a whale's ability to expel water.
• Fin whales need a 15% clear area on their baleen to filter-feed quickly.
• The researchers used frozen krill and a tube to simulate the whale's mouth in their experiment.

Key Terms

Baleen

Special plates in fin whales' mouths that help them filter-feed by letting water through while keeping krill out

Krill

Small crustaceans that fin whales feed on

Kilopascal (kPa)

A unit of pressure, with 1 kPa being equivalent to the weight of a 10-centimeter-square area of water

Implications

This discovery is important because it helps us understand how fin whales adapt to their environment and find food. It also shows us how delicate their feeding process is and how much depends on the balance between water flow and krill buildup.