It is uncommon for lions to actually climb trees because their weight let them down but there are no more than 2 populations in whole world of such lions that do actually climb trees as one of their day after day behavior.
One of these populations is lives within the Ishasha sector found in the southern part of the Queen Elizabeth National Park and the other population is found in Lake Manyara National Park in the Southern part of Tanzania.
It is believed that these lions climb trees as a way of protecting themselves against the numerous tsetse flies that could bite them from the ground, whereas other people claim the they actually climb into the branches to escape from the heat on the ground and enjoy the cool breeze; nonetheless the reason why they climb up into the tree branches remains unknown.
It is much easier to catch sight of a tree climbing lion in Ishasha than any of the other places where the lions are found and they can easily be spotted on sycamore trees. You do not want to miss out on such an amazing sight during your safari to Uganda.
Interesting thing is you will get more than just a once in a lifetime opportunity to see tree climbing lions when you visit ishasha, there is plenty of other wildlife species to see. There are elephants, buffaloes, and numerous antelopes.
If you are planning a safari trip to Uganda, Queen Elizabeth national park is one place not to forget on your safari package, specifically Ishasha on your itinerary.