19 Things You Probably Didn't Know About "The Island With Bear Grylls"

Sometimes their fingernails fall off.

1. In series one, producers added yucca trees and two caiman to the island.

Channel 4

"We had a responsibility to ensure that the habitat of the island would not be damaged by the men's stay," said Bear Grylls. "We added indigenous yucca and two caiman to the existing population on the island so that the men had enough to eat and we did not damage the natural eco system."

2. And in series two, they introduced coconuts, black pigs, and iguana — as well as lining a muddy pool of water.

Channel 4

"I can't drop people on an island where there's no water source and there's no rain and expect them to survive," said Grylls. "So yes, there's water, there's food, but they've got to have the strength, the determination, the resourcefulness."

3. The islanders speak to its producers via radio every day, and they also have access to a satellite phone in case of an emergency.

Channel 4

Of series one, Channel 4's website says, "It was essential that we were able to monitor the well-being of the men and deal with any operational issues (such as damaged camera equipment).

"Production had a daily radio call with the island to check that everyone was safe and provide an opportunity for the cast to report any illnesses, injuries or operational issues."

4. A paramedic can always reach the island within 15 minutes.

Channel 4

According to the Channel 4 website, "If a contributor needed medical assistance, we had 24-hour survival expert and paramedic support on a neighbouring island... The island also had 24-hour support from a helicopter medevac base."

5. And participants are allowed to speak to a psychologist at any point during their stay.

Channel 4

"In addition to emergency medical support, the men could request a conversation with the production psychologist at any time during filming," the Channel 4 website says. "[And] once filming had completed, the men were all provided... with on-going access to the psychologist if the men felt they wanted additional support."

6. Producers and islanders exchange camera memory cards using a drop box.

Channel 4

"Production used a drop box system for picking up and replacing camera cards and microphone batteries," the Channel 4 website says. However, producers make sure that they never physically meet the islanders.

7. And islanders are encouraged to leave foods they are unsure about eating in the box for expert analysis.

Channel 4

"The men were provided with guidance in relation to flora and fauna [but] it was important that they did not take any risks — some of the flora and fauna native to the island is highly poisonous," says the Channel 4 website.

"We encouraged the men to use the drop box if they were unsure as to whether they could eat something. The food would be analysed by our experts so we could confirm to the men whether the food was safe to eat."

8. Two out of 13 of the first series' participants had previously worked with Grylls.

Channel 4

The show includes TV professionals who live among the other islanders, in the exact same conditions. Participants Rupert and Dan had both previously worked with Bear Grylls.

9. In the second series, the islanders accidentally ate an endangered crocodile.

Channel 4

Islanders thought they captured a caiman, but it was in fact an American crocodile, a species which is protected by the federal Endangered Species Act. Channel 4 said, "This was a genuine and regrettable error. Prior to filming experts were consulted to ascertain species on both islands and the American crocodile was not known to be in the area or on the island."

They added: "The relevant national environment agency are aware of the incident and have granted a licence to replace the animal which has now been done."

10. The island made some participants lose their fingernails.

Channel 4

"My fingernails started falling off," said Daniel from series two. "I was sort of rotting in places and I had salmonella poisoning!"

11. Producers are told to intervene if participants ask to leave, hurt themselves badly, or become worryingly close to dying.

Channel 4

Of the first series, Grylls said, "We only stepped in three times. Firstly, if they wanted to leave. Secondly, if there was an accident – someone cut themselves badly or scalded themselves with hot water. The other time we would step in was when they didn't realise how close they were to dying."

12. In series one, producers almost called off the whole show mid-way through filming.

Channel 4

"We were very close to actually calling the whole thing off for one of the islands, just because of how close it got to lasting, long-term, permanent damage, and having a lot of people unconscious, dehydrated in hospital is not a good outcome," said Grylls.

"We were probably an hour or so away from going, 'Right, we're done, forget the TV, forget everything, we genuinely have a duty of care to keep these guys in one piece'."

13. It is possible to take part as a vegetarian.

Channel 4

Jaime did it in series two. "To be honest I found the lack of food easier than I thought – it was the lack of water and dehydration that I really struggled with," she said.

14. Former islanders say that surviving the experience has made them more confident.

Channel 4

"I think it definitely makes you feel you can survive in any situation," said Lauren from series two. "I think I could walk into any country now and as long as I had the basics— something to eat and a little bit of water— I could go."

15. Even though they lost a lot of weight.

Channel 4

"I came home 15 kgs lighter," said Tony from series one.

16. Others say that it had a positive influence on their work lives.

Channel 4

"The island was directly related to my work as a paramedic," said Barney from series two. "There were times there when I was in real pain. So when you see a patient you empathise more."

17. And many participants said their relationship with food changed.

Channel 4

"I found it hard to come back to normal civilization," said Lauren from series two. "I found the amount of access we had to food totally overwhelming."

Chris from series one added, "My diet since I got back from the island has got much better... when I got to the supermarket I'm much more conscious."

18. Some of the participants received death threats after taking part in the show.

Channel 4

"We got quite a bit of hate mail — or I did, specifically, because I killed [the pigs]," said Lauren from series two. "I think someone said, 'I'd like to slit your throat'.

"I think people struggle with the reality of where meat comes from."

19. But they also say that the bonds they formed with each other were truly meaningful.

Channel 4

"The women I experienced it with, for the best part were, and always will be some of my best friends for life," said Lauren from series two. "The bonds we created, the stories shared over late night bonfires were some of the most personal and reflective experiences I've ever dared to have."