06.10.2025 – Spermaceti organ

Today on our trip we encountered some Sperm whales (Physeter macrocephalus). One unique anatomical characteristic is the so-called spermaceti organ. This organ lies over the upper jaw of the sperm whale and is shaped like a elongated barrel. It contains soft and spongy tissues which are saturated with spermaceti. Spermaceti is a wax like structure and scientists think it has two uses. The first is to create sound, the second to help with the buoyancy of the animals. The second is the case as spermaceti has a similar density than salt water, but depending on the temperature the density is lower or higher than salt water. By modifying the blood flow the sperm whale can change the temperature of the spermaceti and with that also the density. As the spermaceti organ is directly under the skin and is so spongy, size changes due to the change of density is not a problem for the animal. It is always fascinating what nature evolved.

By Horst Schulte

Sightings of the day

Ribeira Brava

09:00 Short-finned pilot whales

13:00 Sperm whales

Stenella

09:30 Short-finned pilot whales, Sperm whales

13:30 Sperm whales

16:30 Sperm whales