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Shrieker Screaming.jpg
Classification Animalia Bilateria Cephalopoda Coleoidea Sepioida Vermiformidae Caederus Mexicana
Feature films  
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Portrayed by

The Shrieker (also referred to as "Screechers" by Nancy Sterngood or "Squealers" by Mindy Sterngood and George Meadows) is a fictional species in the Tremors series of films. Shriekers first appeared in Tremors 2: Aftershocks, where they served as the primary antagonists. Shriekers also appeared in Tremors 3: Back to Perfection and several episodes of Tremors: The Series. The Shrieker stage is the second life cycle stage of the creatures featured in the series; the Graboid being the first and the Ass Blaster being the next and final.

The Shrieker can be seen as a kind of pupa without the immobility, or a nymph even though a nymph would be the young beginning stages for animals (insects) with incomplete metamorphosis, the Shrieker being the middle "teen" stage. And the Graboid species clearly shows a complete metamorphosis. Shriekers are arguably the most dangerous form of Graboid, as they reproduce the fastest, can run on land or tunnel underground and have a voracious appetite, necessary for them to grow into Ass Blasters and lay Graboid eggs. However, Burt Gummer has confirmed that Ass Blasters are twice as dangerous as Shriekers.

The name "Shrieker" was given to the creature by the special effects crew of Tremors 2 and later introduced to the audience in Tremors 3.



Shriekers are asexual, and as such only have one role, make more Shriekers, once they eat enough food they reproduce exponentially. When they reproduce, the fetus that is attached to the lining of their stomach\uterus detaches from the lining of this organ. They then open their mouths to the greatest extent and with a good deal of screeching, deposit a fetus on the ground. The baby immediately begins to stand up also it was observed that it already seems to begin to grow. Kate Reilly theorizes that they must be able to repeat this feat, one becomes two, two becomes four. This is proven in later additions and in the same movie in fact it has an unknown number of fetuses lining its stomach/uterus. The process of giving birth can lead to stress however which will eventually lead to death.

Unlike their previous incarnations, the huge, subterranean and limbless Graboids, Shriekers live on the surface. Much smaller than Graboids, Shriekers are about 4 feet long and 3 feet tall with their jaws pieces about one and a half feet long. While Graboids are worm-like in shape, Shriekers slightly resemble dinosaurs or heavy ground-dwelling birds, having stout, three-toed legs and a compact body. They also have a short, stump-like tail. This tail, as well as some small bulges in the neck, has some orange coloring on it. While its function is unknown it could possibly be the early stage of the Ass Blaster tail and could have the chemicals already present in small quantities, or it could even be used in signaling other Shriekers. The one thing that shows Shriekers are related to Graboids is their skull - just like a Graboid's, it consists of a powerful, beak-like armored upper jaw and a much narrower lower jaw and the mandibles have sharp hooks and serration’s, ideal to hold prey. Inside the "beak" is a slightly prehensile tongue that they use to pick up smaller pieces of food or other edible material, they do this by dragging their tongue over the ground. Sometime during their twelve-hour molting it is believed that they lose the ability to duplicate and instead their bodies convert over to being able to lay eggs. After surviving for 24 hours, a Shrieker will molt into an Ass Blaster.

Shrieker in Tremors: Shrieker Island.

Genetically altered Shriekers resemble their non-altered counterparts but they are a gray-ish green color with sickly yellow stripes, a face resembling a skeletal Graboid head, and their heat-sensing organs are always exposed.

Hunting and intelligence

Unlike the usually solitary Graboids, Shriekers are pack hunters, using their numbers to bring down large 

Shrieker's Sensor

prey. In Tremors 2: Aftershocks, the Graboids spawned three Shriekers per worm. This changes in Tremors 3: Back to Perfection, in which Burt explains that one Graboid can spawn six from itself, it was claimed that these were highly evolved ones the spawned more due to an efficient metabolism. Later in the series, it is said that a single Graboid can spawn twelve Shriekers (the number of Shriekers spawned may be related to the food a Graboid has successfully consumed, or how much of the Graboid a Shrieker eats while tunneling its way out).

Shrieker's Thermal Vision

In the second film, it was stated that they only spawn three, but the number seems to be between three and six for each Graboid; as in Night of the Shriekers, the Graboid found by the government in the desert only spawned four. By eating sufficient food of any kind, they have the ability to multiply. The creatures are hermaphrodites, being able to double in number every few minutes. In Tremors 3, the six Shriekers were able to spawn an entire herd in under twelve hours after eating a poultry truck.

When a Shrieker senses heat, it lets out loud screams. This is how Shriekers earned its name. While the sound is useless to each other, as they are deaf, they produce a lot of heat when screaming. This heat alerts other Shriekers to the presence of prey. Another thing unexplained in the films is the Shriekers' ability to "see" heat before raising the frill covering their heat sensor; they always seem to know when to raise it.

It is explained on the Stampede Entertainment FAQ that they can see some heat through the frills. Raising them merely enables them to make full use of the obviously delicate sensory organ, similar to opening one's eyes widely. In an episode of Tremors: The Series: Night of the Shriekers, Shriekers were being trained by a government agency to use their heat-seeking organs to locate people in disaster areas. It has also been theorized that the colorful patches on Shriekers are areas where more blood is near the skin surface. This is to emit more heat than the rest of the body, and that might communicate something to another Shrieker like, “Stay away from my food,” or “Lookout, I’m about to throw up a new baby.”

"You mean that they been acting so smart, because they're so stupid?"
Grady Hoover[src]

When first introduced, they appeared to be so intelligent they would know to wreck cars and destroy radio towers to isolate and slow down their prey. This was later proven to be false as they attacked these objects because they gave off heat, making the creatures think that they were attacking prey. They have been observed attempting to eat warm car engines, electronic cables, and steamed clothes. While this was not seen in Tremors 3, Ass Blaster's have been known to respond similarly.

While hunting, Shriekers show some good feats of insight and cooperation, using each other to form natural ladders to reach prey hiding on high ground such as rooftops. The Shrieker feeding instinct is all about getting as much food as they can as quickly as they can. As a result, they often leave their prey's bones intact (but little else) due to the amount of time and effort required to crunch them open for the marrow.


Shriekers are very dangerous in large packs that can be deadly to any prey.

Strength: Their strength has shown by their powerful jaw to brake though car hood easily by shredding it. Their strength is strong enough to hold down humans.

Speed and Agility: Their ability to move fast on their short legs to catch up to their prey such as humans and make quick turns as they are able to jump.

Hunting: There can go up to six though 100 or even more to take down any prey.

Heat Sensor and Senses: Since they went through the next phase this form has a heat sensor to replace the vibration detector. Their tong is also have strong sense of taste as it can be used to find food on the floor or use to help track prey as proven to taste the ladders that Earl and the rest had climb.

Intelligence: Though they stay together in numbers for safety and took the amount of time to figuring way how to get prey from high ground by jumping on each other back to make a similar ladder of their own to reach their prey. One survivor was able to grip on to Burt's truck.

Endurance and Stamina: Able to travel long distances without showing any sign of being exhausted just like their previous form of Graboid. Though their endurance is weaker then Graboids since losing tougher hide as they can be easily be killed by bullets.

Prehensile Tongue: Unlike their previous form they don't have Grabbers of snake-like tongues through their tongue still can grab objects. Their tongues are the three tentacles fused together, as it can be seen that there are three "bump-like" protrusions at the tip.

Reproducing Growth Rate: They can release one egg possible for a short period of time that can grown very fast to full size in minutes.

Heat Screeching Contacting: They can release heat that can contact others of their kind by using a call.

Bio-Acoustic Scream: The genetically enhanced Shriekers can emit a devastating sonic scream which can bring their prey to their knees.

Reproduction and Birthing Rate

After an indeterminate time spent living underground, a Graboid surfaces and undergoes a gory metamorphosis: It is pregnant with three to twelve Shriekers — fast-moving, lion-sized bipeds. Once the Graboid dies, the Shriekers eat their way out of the dead Graboid and proceed to multiply exponentially once they eat.

Shrieker Regurgitating another one

These extremely dangerous creatures reproduce asexually— in effect, each Shrieker is "born" pregnant. Shriekers' ability to reproduce is limited only by their access to food. Once a Shrieker has eaten enough food, it disgorges a new, ravenously hungry Shrieker that starts out 1/4 of the size of the adult but rapidly grows. Consequently, it is crucial that Shriekers be prevented from getting too plentiful food.

Shriekers multiply when they eat, so there is there a chance that there are only three Shriekers in each Graboid to start with. Depending on how much each one eats while escaping, however, determines whether there are more Shriekers after the primaries escape. So there only maybe 3 in the beginning but when they come out there may be up to twelve. Another theory is that they only eat a little each, making a small opening to get out. Thus, this would mean there are only three birthed from a single Graboid in certain cases.

Even though Shriekers, like Graboids, are technically blind, they can track their prey by sensing infrared radiation. They are especially sensitive to temperatures between 97 and 107 degrees F. — the normal range for mammalian body heat. Shriekers also feed on cold objects, which they find by dragging their tongue over the ground or because they detect a lack of heat. They have been observed eating military rations, and could possibly also feed on plants, which would make them omnivores.

Shrieker Youngling

Shriekers' prolific reproductive skills make them so dangerous that the U.S. government has decreed they are not a protected species and should be killed on sight.

Shriekers will turn into Ass Blasters if there is a large supply of food nearby and they have at least given birth to one Shrieker each.


If you encounter a Shrieker in the wild, do anything possible to mask your body heat. Thermally insulated blankets are effective camouflage against a Shrieker's infrared senses, but be certain to cover yourself entirely. Your exhaled breath can be a fatal giveaway if the ambient temperature differs from your body's internal temperature. If you are in a vehicle just like Graboids do not let your engine idle and make sure it has cooled off before you park it or the Shrieker will be attracted to the heat and will eat you. NEVER FEED A SHRIEKER! If you feed a Shrieker it will spawn another one and you can get up to 24 of them because they spawn in multiples of six. Also never leave food or livestock unattended or the Shriekers will eat it and transform into Ass Blasters which are more dangerous.

Known Individuals

Notable Incursions

Created by

Ron Underwood, Brett Maddock, and S. S. Wilson


  • S.S. Wilson has named the Shriekers the single greatest threat in the Graboid life-cycle due to their reproductive abilities. Burt Gummer has argued that Ass Blasters are harder to fight than Shriekers, though Ass Blasters do not reproduce as rapidly as Shriekers do. 
  • While it is unknown who named the Shriekers, it is likely (given the franchises' tradition) that Grady Hoover named them.
  • The African Graboids appear to have evolved to the point they straight up become African Ass Blasters; skipping the Shrieker phase altogether.