1. Differing flippers: The sea lions have longer hindflippers that they could rotate allowing them to assume a sit-like position and walk on land. The harbor seals have shorter hindflippers that are angled backwards and not capable of rotation. They could not use their hindflippers for sitting or walking, thus they rest by lying flat on the ground, most of the time on their belly.
The foreflippers of sea lions are longer and skinnier. The seals' foreflippers are stubby and hairy.
2. Differing ears: Sea lions have smal earflaps that you could see, true seals look earless because they only have earholes.
Could you now tell which of the two pictures above are the sea lions and which are the harbor seals from the differences I mentioned? If not, read on, as I will add more differences in this post. Meanwhile, let me share with you a common sea lion and harbor seal behavior that I shared with a visiting tourist who was planning to snorkel in La Jolla Cove. A lot of tourists (and locals too), usually find delight in seeing the harbor seals and sea lions in their natural habitat. They are sure cute and fun to look at. However, they can be intimidating for those who are swimming near them for the very first time.
Anyway, let me give you a quiz now identifying harbor seal and sea lions basing from their appearance. Remember, sea lions rest like in sitting position, whereas harbor seals lie flat on their belly because they could not rotate their shorter flippers. Also, you won't see earflaps in seals because harbor seals only have earholes. Also, seals are more hairy or furry than sea lions, they may be gray in color, black, or spotted brown. Whereas sea lions are brown in color. If you are in La Jolla, obviously you could identify them, sea lions are noisy, VERY NOISY, whereas harbor seals are quiet and peaceful!
Is this a seal or sea lion?