They are trying to protect the only thing they know is theirs. You see Rick Marshall my people live in this city they know are ancestors built it. But they do not know how or why it is the only thing my people have to make them secure. Those of are people who have ventured across the split in the earth have never returned and so we stay here and protect what is ours from anyone who intrude. But are ancestors become war like and barbarian they destroyed each other those that remained were the strong and uneducated.
~ S'latch talking about the Sleestaks
The Sleestak are a species of large green-hued sapients notable for a combination of both reptilian and insectoid features. According to the Library of Skulls, their population is quite minor, with only 7,000 existing.
In the 1974 TV series, the Sleestak Leader was portrayed by Jon Locke, while all of the other Sleestaks were portrayed by Jack Tingley, Mike Westra, Scott Fullerton, Dave Greenwood, Bill Laimbeer, John Lambert, and Brian Heublein. In the 2009 film, Enik was portrayed by John Boylan, while all of the other Sleestaks were portrayed by Kurt Carley, Travis Samuel Clark, Daniel George, Todd Christian Hunter, Marti Matulis, Tim Soergel, Douglas Tait, Patrick Wedge, Landon Ashworth, Seth Bauer, Trevor Brunsink, David Craig, Ben Hansen, Shane Huseman, Danko Iordanov, Kenny Jackson, Matt Kavanaugh, Darren Kendrick, Frederick Keeve, Terence Leclere, Nathan Luginbill, Christian Pogorzelski, Loyal Thomas Ruddell, David Szabo, Nathan Udall, Kyle Weishaar, Joey Zadwarny, Kyle Derek, Neo Edmund, Michael Gervasoni, and Ray Quiroga.
The Sleestaks are regular antagonists in the original series. In the first two seasons, they often attacked the Marshalls when they got into Sleestak territory. In the third season, they become even more villainous after gaining a Sleestak Leader since they actively seeking ways to destroy the Marshalls.
The Sleestak Leader is a major antagonist in the 1974 TV series Land of the Lost. He is portrayed by Jon Locke.
The Sleestak Leader differs from the other Sleestaks because he wears a distinctive pendant. He is also able to speak fluent English. He is the ruler of all Sleestaks and he is very hostile toward the Marshalls. He is often seen discussing with Enik (most of the time about the Marshalls), and though he doesn't seem to appreciate him, he tolerates him. Like all Sleestaks, he has a great respect for the Library of Skulls.
Land of the Lost (1991 TV series)
In the 1991 TV series, the only Sleestaks seen are a group of criminals under the leadership of Shung. In this series, they have an appearance closer to that of the native dinosaurs than those in the 1974 TV series and 2009 movie.
Land of the Lost (2009 movie)
In the movie, the Sleestaks serve as primary antagonists. Originally, they were under the leadership of The Zarn, but they were enslaved by the Tachyon-manipulating Enik after he killed him.
In the film, it's revealed that Sleestaks can reproduce rapidly and that they possess a secondary set of jaws that are only visible when attacking (contrary to the 1974 TV series where the Sleestaks are toothless).
In the past, the Sleestaks condemned Enik the Altrusian to be imprisoned for 10,000 years for his genocidal crimes. However, he manages to escape and murders The Zarn, the current ruler of the Sleestaks. He uses Tachyon Crystals to control the Sleestaks and plans to send his army across time and space to invade and conquer the World.
Long after, the paleontologist Rick Marshall and his friends Holly and Will arrive in The Land of the Lost and Enik sends them telepathic message to tell them to come see him in the Central Pylon. However, after coming they are attacked by the Sleestaks and are forced to took refuge into the Pylon.
The following day, Holly is captured by non-controlled Sleestaks for assisting Enik, but Rick and Will save her from being executed and kill the Sleestaks. Enik later arrives with his army of mind-controlled Sleestaks and sends Grumpy to attack them, but the dinosaur finally befriends Rick and defeats the Sleestak army.
After Enik's fail, Will mentions that he has lost control over the Sleestaks and has been attacked by them.
At the end of the film, an egg that was brought by Rick on Earth is seen hatch, and it turns out to be a baby Sleestak.
That is a problem you see my people aren't intelligent.
~ S'latch talking about the Sleestaks
There is no need I will tell them to leave. Why are they firing at us we aren't threatening them.
~ Enik trying to stop the Sleestak from attacking the Marshall family
They happen to be vicious and warlike.
~ Rick Marshall telling Enik about the Sleestaks
That will not be necessary we already know that you lie.
~ Sleestak Leader to Rick after he didn't talk to the Sleestak Skulls
Not only unfriendly but dangerous. Don't have anything to worry about they can't stand the light or the heat so they don't ever come out in daylight.
~ Will Marshall telling Uncle Jack about the Sleestaks
When the humans learn their friend Enik is in danger they will take whatever steps necessary to save him.
~ Sleestak leader using Enik as bait for the Marshall's