After you prove the other three cryptids (Nessie, Chupacabra, and Jersey Devil), Mews will give you another place to go on the helicopter -- the Pacific Northwest where Bigfoot has been sighted.
Follow Bigfoot in the copter as he tries to hide under the trees. Gretchen will arrive and put him in a cage. Jump to her helicopter and click the fuel tank, then cut the rope holding the cage. You and Bigfoot float down safely.
GLITCH
If Bigfoot or your copter freeze up, there is no way to complete the quest. The only sure solution found is to go to the small map at upper right and Restart the island (ouch). Before you do, try leaving the island, playing on another island, and then coming back to see if this resets the helicopter scene.
just keep following from a distance
A gorilla
You can't, because it never appears. You do find Bigfoot at the end of the quest. All you can do at the Himalayas is get the lantern from the monastery and a photo of a footprint high up on the mountain. This is not enough proof. When you prove the other three cryptids, Mews will send you after Bigfoot instead.
You get the Island Medallion after you prove the existence of three of the four cryptids, and rescue Bigfoot from the evil Gretchen Grimlock. (see related question)
When you catch Gretchen Grimlock's helicopter, jump onto it from yours, then click her gas cap and fuel will start coming out. Cut loose the line to Bigfoot's cage with your gardening shears, and you both float safely down on the cage's parachute.
He is in the Pacific Northwest, where he lives in a cave. Once you have confirmed the other 3 cryptids, you can go there and follow him in the helicopter.
Yes, you can find proof of The Jersey Devil, Bigfoot, Nessie, and the Chupacabra. (see related question)
just wait for it to move the follow with helicopter
first you have to find all the other cryptids then you go in the helicoptor to the new location and follow him to his cave
After you have confirmed the other three cryptids (Nessie, Chupacabra, and the Jersey Devil), and brought back the inconclusive footprint from the Himalayas, Mews will send you in pursuit of Bigfoot, which is similar to the Yeti.
Reboot Poptropica if either the Helicopter or Bigfoot stops moving. This is a known glitch affecting less than 1% of Poptropica players on the island.
After you only get a footprint photo from the Himalayas, Mews decides that it is too difficult to track the Yeti. When you prove the other 3 cryptids, he sends you in search of Bigfoot, and you have to rescue the creature from the evil Gretchen Grimlock.