"Relax? With three giant alligators knocking the house down?"
— Dr. Orchard

"Attack of the Alligators!" is the twenty-third episode of Thunderbirds Season 1, first broadcast on March 10th, 1966. It was the 24th episode produced.

A scientist in South America develops a growth substance, a small sample of which gets into the river and causes three alligators to grow to giant sizes. The residents of his house barricade themselves inside whilst the enraged animals gradually beat down the house.


A businessman called Blackmer visits the reclusive Dr. Orchard, a scientist who lives in a remote house on the Ambro River in South America. From the local plant Sidonicus americanus, Orchard has developed a food additive called "Theramine" which, if fed to animals, causes them to grow considerably beyond their natural size. Enlargement of animal stock around the world would offer a simple solution to famine and other financial advantages.

Blackmer's boatman, Culp, has been eavesdropping on the meeting. A storm forces Blackmer to stay at Orchard's house for the night. Resolving to abscond with the Theramine and become rich, Culp waits until the other occupants are asleep and steals the keys to Orchard's laboratory from the housekeeper, Mrs. Files. While filling a vial with a quantity of Theramine, Culp accidentally knocks the rest into a sink and the chemical drains into the Ambro River. When Blackmer and Culp leave Orchard the next morning, their boat is ravaged by an alligator, now expanded to an extraordinary size due to the contamination. Orchard's assistant, Hector McGill, manages to rescue Blackmer, but Culp is apparently killed and the house is quickly surrounded by three giant alligators, which proceed to attack it with Orchard, McGill, Blackmer and Mrs. Files trapped inside.

Thunderbirds Attack of the Alligators

Oversized alligators attacking the house where Blackmer, Mrs. Files, Dr Orchard, and his assistant, Hector McGill, are trapped.

On the advice of Mrs. Files, McGill contacts International Rescue and John relays the incredible details to Tracy Island. Jeff orders the launches of Thunderbirds 1 and 2. Arriving at the scene, Scott wards the reptiles off with his hoverjet missiles and enters Orchard's house through the laboratory window. Eventually the alligators cause so much damage that the laboratory caves in, forcing Scott and the others to escape to the lounge. The group is confronted by none other than Culp, who survived the alligator attack and holds them all at gunpoint.

Virgil arrives in Thunderbird 2 and repels the alligators away from the house with the vertical thrusters. Alan and Gordon man tranquilliser guns and subdue two of the creatures. When the third returns to the house, Alan leaves Thunderbird 2 on a hoverjet to lure the alligator away. Although Alan fails to notice a tree in his path and falls from his hoverjet, Gordon saves his brother by neutralising the last alligator. Culp threatens to pour the whole Theramine vial into the river if he is not granted passage upstream. Launching Thunderbird 4, Gordon discovers a fourth, even larger alligator which attacks the boat and kills Culp before being killed by Virgil with a missile from Thunderbird 2. Despite fears that the vial has been smashed, Gordon retrieves it intact.

Back on Tracy Island, Jeff announces that Orchard and Blackmer are putting international restrictions on Theramine. Tin-Tin has been away from the island on a shopping trip and tells Alan that she has purchased a present for his upcoming birthday — it is revealed to be a pygmy alligator.

Regular Voice CastEdit

Guest Voice CastEdit

International Rescue Equipment UsedEdit

Non-International Rescue Equipment UsedEdit


  • This episode is a favourite among fans for its use of real alligators (or rather, real crocodiles). Some members of the production team had the RSPCA called in during filming, though the RSPCA representative ended up giving the crewmembers advice on the voltage that would be needed to make the alligators move. Nevertheless, visual effects director Brian Johncock declined to play any part in the making of this episode, as he thought that the use of electricity to encourage the crocodiles to move when needed was unnecessarily cruel.
    • One of the RSPCA members even became part of the production crew after he stated that Thunderbirds was his favourite television series.
  • The stock footage of the thunder sky was later used for the opening titles of ITC series The Prisoner.

Thunder Sky

  • Although he did not write this episode, it is possible Dennis Spooner may have reused the idea of an enlargement drug being washed down a sink causing animals to grow for Gnaws, one of his episodes for The New Avengers. In that, a giant rat was substituted for the giant alligator.
  • This episode was filmed late in 1965.


  • The camera and its operator can be seen reflecting off the window as Mrs. Files watches Blackmer and Culp arrive at the beginning.
Goof 1 ep24
  • Jeff suggests that Pod 6 should be used, but if you look closely as Thunderbird 2 releases the pod, you can see that Pod 4 has been selected.
  • When Culp is walking from his boat to the outside lab window, some dialogue from Dr. Orchard describing the theramine process can be heard in the background. In the next scene, the same process is described with the very same dialogue soundtrack.
  • When one of the alligators attacks Blackmer and Culp, the first splashing results in their clothes getting wet. However, on the second splashing, their clothes are dry.
  • When the third giant alligator turns over after being shot at by Gordon, a bit of water can be seen jumping into the air at the very end of the shot, indicating that the shot was played backwards in order to achieve the effect that the crew wanted.


Main article: Attack of the Alligators!/Transcript

Alternate VersionsEdit

Thunderbirds (Fox Kids Series)Edit

Main article: Attack of the Alligators (Fox Kids Series)

Turbocharged ThunderbirdsEdit

Main article: Attack of the Alligators! (TCTB)

Foreign TitlesEdit

Attack of the Alligators (Italian)

Italian 8mm home movie

  • French: L'attaque des alligators
  • German: Angriff der Alligatoren
  • Spanish: El Ataque de los Caimanes
  • Italian: La battaglia degli alligatori (8mm); L'attacco degli alligatori
  • Dutch: De krokodillen vallen aan (TV); Monsterlijke dreiging (VHS); Aanval van de alligators! (VHS, DVD)
  • Japanese: 大ワニの襲撃

Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.