A lake of stingless jellyfish. They lost the ability to sting through evolution. It is called Lake Kakaban, on Kakaban Island in the Derawan Islands of East Kalimantan.
About two million years ago, tectonic movement lifted the coral reef in this area. Part of the sea was trapped in the middle of the island, fully isolated from the open ocean. In that sealed lake live four kinds of jellyfish: the moon, the spotted, the box, and the upside down, which swims with its tentacles facing up.
Because no predator can get in, no turtles, no large predatory fish, the jellyfish here never needed to defend themselves. Over millions of years without threat, their stinging cells were reduced. Slowly they disappeared, because they were never used. Today there are only two countries like this in the world: one in the Palau Islands of Micronesia, the other in Indonesia.
More surprising still, Indonesia has 11 such lakes, or even more:
- 01Lake Kakaban, East Kalimantan
- 02Lake Mariona, Central Sulawesi
- 03Lake Paisu Batongan, Central Sulawesi
- 04Lake Lohia, Southeast Sulawesi
- 05Lake Sombori, Central Sulawesi
- 06Jellyfish Waba, Misool, Raja Ampat
- 07Lake Lenmakana, Raja Ampat
- 08Lake Karawapop, Raja Ampat
- 09Lake Mangiatan, East Nusa Tenggara
- 10Lake Pulau Sembilan, East Nusa Tenggara
- 11Lake Tumalol, Raja Ampat
