We've seen those Fast Biters with Red Claw.
Screech and Thud are a pair of "Fast Biters" (the series' term for dromaeosaurs, or raptor dinosaurs; they are Deinonychus specifically), and the subordinates of Red Claw. Pete Sepenuk plays Screech, while Rob Paulsen plays Thud. They are the secondary antagonists of The Land Before Time television series.
Symbiosis with Red Claw
There seems to be a symbiotic relationship between Red Claw, Screech and Thud as Ruby has once said "Wherever Screech and Thud are, Red Claw is never far behind". Also, in at least one episode, "The Hidden Canyon", the Fast Biters led Red Claw to a breach in the wall protecting the Great Valley from Sharpteeth.
In "Return to Hanging Rock", Screech and Thud have been seen hunting without Red Claw. Red Claw appears by himself without them in the same episode, so it seems that they split up from time to time to hunt (or in the fast biters' cases) scout out. This may be why Screech and Thud enter the Valley without their leader.
How or why they hunt together is unknown, though it could do with simple symbiosis: Screech and Thud use their smarts, small size and greater agility to access places Red Claw can't get to when hunting and flush out prey while Red Claw's brute strength and ferocity protects them from being attacked or eaten themselves and guarantees them an easy meal. This is shown in "The Cave of Many Voices" and "Escape From The Mysterious Beyond", as Red Claw had to call in the Fast Biters to chase after the children through areas he could not reach.
Nonetheless, it is almost impossible for Littlefoot and his friends to encounter one without encountering all three and at full strength (barring Red Claw's two final appearances, though they are only cameos and the former is an encounter that only involved Chomper, in the latter he did not find any characters).
Screech and Thud's first appearance is in this episode, alongside their leader, Red Claw, chasing away a family of Parksosaurus in order to get a drink. Red Claw eventually a hole leading to The Cave of Many Voices after hearing the laughing of the gang. Meanwhile, Screech and Thud get something to drink.
Later, Red Claw decides that they will be breaking their way into the cave. Screech and Thud walk over and try to push away the rocks, to no avail, before Red Claw pushes them away and starts getting the job done himself. Soon however, he walks away, and the fast biters start clearing away rocks that had been broken down by the Tyrannosaurus. After a long time of clearing rocks, they soon create a hole big enough for Red Claw to fit in, and so they enter the Secret Caverns, presumably to search for the children. Inside the cave, the kids see them and Red Claw, but Littlefoot, Cera and Chomper fall off the cliff they were watching them on, and the sharpteeth see them and give chase.
After Red Claw cannot chase the gang any longer, he sends the fast biters to go after them in the more cramped areas of the caves. They try and nearly grab the kids multiple times, though ultimately fail, as the kids go into narrower areas, and lastly, a spot where they slide down to finally escape the fast biters.
Soon, however, the fast biters find the kids again, who were being pursued by Red Claw. The gang easily escapes the three sharpteeth, and they quickly begin to sniff out the children. Ducky sneaks past them and into the Cave of Many Voices, scaring the sharpteeth just before Red Claw detects the rest of the gang. The rest of the children then enter the cave as well, and yell loudly, scaring Screech and Thud away.
Screech and Thud, along with their leader, make a flashback appearance in this episode. Red Claw signals them to follow Chomper and Ruby instead of the latter's parents, who had just left them. The fast biters chase Chomper and Ruby with Red Claw not far behind, through narrow canyons. They almost catch and kill them, though the two children then enter a small cave and hide from them. Red Claw cannot find them, so he signals his fast biters to follow him, and they leave the area.
Screech and Thud appear near the end of the episode in an ambush attack. They emerge from a group of bushes as soon as Red Claw attacks. Red Claw signals the two fast biters to chase after the children, while he sticks behind. The three sharpteeth follow the gang out of the forest, until they trap them at a wall of
Screech and Thud's (more-so Thud's) most major appearance is in this episode. After the kids cross some narrow cliffs that Red Claw could not get onto, he sends Screech and Thud after them. The raptors chase the children across the narrow cliffs, though Thud nearly falls off. The kids then hide in a small rocky area with boulders around them, while Thud tells Screech to split up, knowing that the kids have hid over there. Thud soon finds Chomper and the rest of them, and calls out to Screech that he has found them. Suddenly, an earthshake occurs, knocking down Thud. Chomper and Ducky are taken away by the ground collapsing.
Later, Chomper and Ducky find themselves on a cliff edge, and they think they are alright - the rest of the gang are going to find a way to get to them and rescue them. Thud soon emerges from the rocks after the rest of the gang leave, and almost ends them, but can't reach because his tail has become stuck in rocks. The kids still cower in fear from being so close to a mean sharptooth, but soon calm down.
Meanwhile, as the kids are walking around the cliff areas, looking for a way to get to Chomper and Ruby, they are attacked by Screech, who emerges from the rocks and nearly eats Cera. He chases them back along the narrow cliffs, and back the way they came, where Red Claw is waiting for them. Screech rejoins his leader, and the two abandon Thud and pursue the kids.
Back at the cliffs, Thud continues to try and bite and claw at Chomper and Ducky. Ducky nearly falls off the edge, to which Thud understands and says he can't eat them if they fall. Chomper then tells him in sharptooth language that he is not going to hurt her, to which he replies, asking if he is going to eat her himself. Chomper roars back, saying that she is his friend, to which he starts laughing.
Back in the forest and plains area, the gang lose Red Claw and Screech for the time being, while a mini earthshake occurs at the cliffs, causing a large rock to fall on Thud's stuck tail, further increasing his pain. Ducky feels bad for him, and walks up to the Fast Biter, but Thud nearly grabs her. Chomper tells him to not hurt her, because if he does, he will stop him. Thud then starts laughing again. In the meantime, Chomper and Ducky sing Everything Will Be Okay. Later, the rest of the gang are spotted by Red Claw and Screech again.
The kids run away, though Screech catches up to them and jumps in between two trees, ready to kill. The gang quickly hide under a mass of tree roots, though Ruby is caught behind and Screech sticks his head in, nearly grabbing her, before she escapes into the roots.
Back by the cliffs, Chomper and Ducky are growing increasingly cold, to which Thud tells them that their friends are not coming back. Chomper then tells him to be quiet. thud responds with saying Chomper is all alone, before laughing again. He then asks to him as to why anyone would want to help a little biter like him. Chomper then yells out in leaf eater language that he is not little.
Later, Thud starts to be in pain again, and Ducky feels sorry for him, but not sorry that he cannot reach them, after lashing out at her once again. Soon after Ducky cheers Chomper up, the rest of the gang soon arrive to help, and push a tree over the crevice below. Petrie sees Thud and yells, though he is stuck. Chomper starts to head across the log, but feels pity for the fast biter, and decides to be the "bigger sharptooth" and help Thud. He clears away a fair amount of rocks for him, and tells him not to eat him, as he is being nice. Thud seems to agree on this, and lets him go. Chomper crosses and Spike pushes the log over to stop Thud from crossing, though soon after they leave, he leaps over the crevice, grabs onto the edge, and pulls himself up. He then runs across the cliffs to get back to Red Claw and Screech, who once again find the children in the forest.
Thud soon rejoins his comrades, and chases the kids into a canyon. They hide in a small cave, and the sharpteeth then search for them. Thud then finds them, but decides to let them off just this one time, for Chomper has saved his life. He then misdirects Red Claw and Screech and they all run away.
After the kids eat a large number of treesweets in the Hidden Canyon itself, Screech and Thud are able to enter the Great Valley at nightfall. They charge in, looking to instill fear into any leaf eater they come across. The fast biters chase a portion of the Valley's population until they reach the walls of the paradise.
Many of the adults quickly spring into action, bringing their children to safety, while the others, including Grandma and Grandpa Longneck, and Daddy Topps, form a group to fight off the sharpteeth. As the fast biters get closer, a duo of Flyers drop treesweets on their heads, a fruit that sharpteeth hate. The Flyers swoop down and try to hit the fast biters, though they manage to avoid their attacks. Grandma and Grandpa Longneck then move in to help.
Thud turns and charges at Grandpa, though he a sent flying through the air from the huge tail of the longneck and crashes to the ground above Screech. Screech looks on frightened, but turns toward Grandpa and prepares to attack regardless. He leaps into the air, and grabs onto the neck of the old longneck, but is thrown away from the massive power of the dinosaur and crashes into a wall next to the downed Thud. The sharpteeth then get up and run away, while Topps and another threehorn chase them out of the Valley.
The next day, the children find the entrance to the Mysterious Beyond, and find the footprints of the fast biters. Later, when the gang, Grandpa and Topps enter the Hidden Canyon to check up on the number of treesweets, Screech and Thud's shadows are spotted. Screech's screech is heard by Ruby, and then the dinosaurs spot the shadows of the fast biters returning. But this time, they bring their leader, Red Claw, with them for a final battle. The fast biters do not see the adults at first, but Red Claw eventually spots them trying to stand still (which does not work with sharpteeth in the Land Before Time universe, despite what Chomper says), and the fast biters then spot them too. The three sharpteeth move in, and Red Claw battles Topps while Screech and Thud fight against Grandpa Longneck again.
Soon the fast biters move closer, and Grandpa swings his tail, nearing hitting them, though Screech narrowly jumps over the tail, and Thud dives under it. While the kids are gathering treesweets pelt at the sharpteeth in order to help, the sharpteeth pick their time to attack. Screech moves in, and signals Thud to attack. Thud leaps into the air and tries to bite Grandpa Longneck, but Grandpa moves out of the way, and the fast biters lands near him. Right after, Grandpa throws Thud into the air with his head, sending him crashing to the ground. The sharptooth quickly recovers, just as Screech nears his moment to attack. Both Fast Biters charge at once, but they are hit by some oncoming treesweets pelted by Littlefoot. The rest of the gang all hit them with dozens of treesweets, and the two Fast Biters run away for good.
Screech and Thud do not appear in this episode, but they are mentioned by Cera. When the gang hear Red Claw's roar, she says "Unless Chomper here can teach Red Claw and his pals some manners."
Screech and Thud's final appearance is in this episode at night time, separate from Red Claw. The two Fast Biters briefly appear when Ruby, Ducky, Spike, and Chomper are adventuring in the Mysterious Beyond in an attempt to find Hanging Rock after hearing the yells of Ducky, who was looking for Spike. They first appear with Screech screeching at them, before Thud lunges at them. He misses and crashes into a tree, causing him to flip over. The kids go under and past a rock, where Screech misses biting them and gets his head stuck temporarily. This gives the kids time to escape, but Ruby trips and falls, hurting her ankle. The Fast Biters then return into view, and chase the kids again, with Ducky, Spike and Chomper having to carry Ruby.
Later, the kids manage to hide from them in a small cave, just before the sharpteeth pass by. They soon turn around and come back, but Skip directs them into an alcove, causing Screech and Thud to lose them. The two Fast Biters are last seen a little bit later on into the episode, still looking for the children, while more flying rocks are falling from the sky. Skip again shows them where to go, and they do not see the fast biters again.
- Screech and Thud may be siblings, though this was not confirmed over the course of the series.
- Curiously, Screech is credited as "Howler" in the credits for "The Star Day Celebration". It is unclear as to why he is referred to as such, though "Howler" may have been his original name from when the series was first being made, with "Screech" being a change made late in production for unknown reasons.
- Howler and Thud perhaps does not sound as good as Screech and Thud.
- A Deinonychus that resembles Screech appears in the episode "The Spooky Nighttime Adventure", during Petrie's 'Sharptooth Flyer' story.
- A noticeable error its that Screech and Thud have two fingers, despite the fact that real life dromaeosaurs sport three. This is somewhat remedied with the discovery of the dinosaur Balaur bondoc, a stem-bird with two fingers on its hands and two sickle-claws on its feet.
- Despite Screech and Thud being credited as being voiced by two different voice actors, they sound the same.
- In "Escape From The Mysterious Beyond", Thud seems to overhear and understand what Chomper and Ducky say to each other. When Ducky says "I hope they get here soon", Thud responds with "Your friends aren't coming back, little biter." This seems to imply that Thud is capable of understanding, though not speaking, leaf-eater.
- Thud also calls Chomper 'little biter', which may be a term designated for young or small Sharpteeth.
- Thud seems to be more sympathetic and good-sided than Screech. He promises not to eat Chomper after the young sharptooth helps him be freed from his tail being stuck under rocks. He later misdirects Red Claw and Screech when he notices where the gang are hiding.
- Screech looks very similar to the blue Fast Biter from The Land Before Time XI: Invasion of the Tinysauruses, except that the sharptooth from the film has red eyes instead of yellow.
- He also looks like the Sharptooth Mom from "The Great Egg Adventure", but again, she has red eyes instead of yellow.
- Screech may have gotten his name from a screeching sound that he makes because Ruby said "That sounded like Screech's screech!" in "The Hidden Canyon".
- This is a sound that Thud and other fast biters do not make. It is heard throughout the episodes, another one known instance is where he is walking towards Grandpa Longneck in the same episode; he makes a screeching sound.
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- They are referred to with masculine pronouns on multiple occasions.
- The Land Before Time TV series episode, "The Star Day Celebration" credits.