Do whales have knees? This might seem like a strange question at first, but when photographed from certain angles, there does appear to be something knee-like beneath their body (see photo link below). So, let’s get to the truth, do beluga whales have knees?
No, beluga whales do not have knees, however, they have thick abdominal fat pads running along the front of their body which can be mistaken for knees. These fat pads are often tensed to maintain balance whilst swimming which pushes them outwards making them look like knees.
Keep reading to find out more about why these fat pads are a great alternative to dorsal fins
Do Beluga Whales Have Knees?
Watch the video version here, or scroll down to keep reading below:
There’s a common misconception that’s been spread around the internet that Beluga Whales have knees, this all traces back to these images on imgur that appear to show a knee-like bone on their underside.
These are genuine photos, however, this is not a knee, it’s an abdominal fat pad that’s used to help them maintain stability whilst swimming.
Beluga whales don’t have fins on their back like fish or dolphins (more on the reasons for this below), instead, they rely on a large ridge on their back and these fat pads on their front to remain stable in the water.
Their abdominal fat pads are made up of blubber and run from just below their front flipper down the side of their body to their pelvic region1 (source: A.J. Werth and T.J. Ford Jr, Marine Mammal Science, Vol 28, Issue 3, 2012).
When they roll or swim upside down, they will tense and raise these fat pads for balance, pushing them up to 14cm outwards and up to 12cm to the side 2(source: A.J. Werth and T.J. Ford Jr, Marine Mammal Science, Vol 28, Issue 3, 2012). This is why it can sometimes appear that they have knees when photographed from beneath during certain swimming maneuvers. Some people have also referred to these as ‘love handles’.
Why Don’t Beluga Whales Have Dosal Fins?
As mentioned earlier, beluga whales do not have dorsal fins which are the fins located on the back of most marine vertebrates including fish and some marine mammals such as dolphins.
The main purpose of a dorsal fin is to provide stability whilst swimming3 (source: Science Direct). So why is it that some marine mammals, like the beluga whale and closely related narwhal, don’t have a dorsal fin?
According to the World Wildlife Fund, this is an adaptation to their cold arctic environment.
Remember, unlike fish, marine mammals are warm-blooded so they have to maintain a certain body temperature to function, even whilst in the cold ocean. However, dorsal fins contain blood vessels that can allow heat to escape4 (source: E. Fougeres, et al., Journal of Experimental Biology, Vol. 205, Pt. 22, 2002). Beluga whales do not have dorsal fins, this minimizes their surface area which allows them to conserve more heat in the cold arctic waters.
The lack of a fin also allows them to travel closer to the surface sea ice5 (source: Whale and Dolphin Conservation) and means they can use their back to break open holes in the ice so they can breathe.
But they still need to maintain stability whilst swimming, so instead of a dorsal fin, they have a dorsal ridge along their back6 (source: Seaworld) and abdominal fat pads along their front which are often mistaken for knees.