Here is a concise summary of the provided text:
**Title:** Cuttlefish Facts
**Key Points:**
1. **Classification:** Cuttlefish are cephalopods, not fish, related to octopuses and squids.
2. **Unique Features:**
* Possess an internal "cuttlebone" for buoyancy control.
* Have 8 arms, 2 long tentacles, and razor-sharp beaks.
* Covered in suction discs for snagging prey.
3. **Camouflage:**
* Can change color, texture, and shape to blend in.
* Have approximately 200 chromatophores per square millimeter.
* Can camouflage in complete darkness.
4. **Behavior:**
* Use color-changing for "disco fighting" (intimidating rivals).
* Employ hypnotic light shows to lure prey.
* Males can disguise as females to deter rivals.
5. **Intelligence:**
* Can count up to at least 4-5 items (demonstrated in a shrimp-choice experiment).
6. **Life Cycle:**
* Females lay hundreds of eggs, which hatch into miniature cuttlefish after 2 months.
* No immature stage; young cuttlefish resemble adults.
**Additional Note:** The summary ends here. The original text also includes a sponsored segment promoting Brilliant.org for math learning, which is not included in this concise summary.
Here are the key facts extracted from the text, numbered and in short sentences:
**Biology and Classification**
1. Cuttlefish are cephalopods, not fish.
2. They are cousins to octopuses and squids.
3. Cuttlefish have a unique internal shell called the "cuttlebone" made of aragonite.
**Physical Characteristics and Abilities**
4. The cuttlebone controls buoyancy, allowing cuttlefish to change density.
5. This enables them to move and maintain position with minimal effort.
6. Cuttlefish have eight arms and two long tentacles with suction discs.
7. They can paralyze prey with strong venom before swallowing.
8. Cuttlefish have roughly 200 chromatophores per square millimeter.
**Habitat and Distribution**
9. There are around 100 species of cuttlefish, varying in size (2.5cm to 90cm long).
10. Cuttlefish live primarily in warm, shallow waters worldwide, except in the Americas.
11. Their absence in the Americas is likely due to the severing of the warm, shallow water bridge between Africa and South America.
**Behavior and Camouflage**
12. Cuttlefish can change color, texture, and shape to blend into their environment.
13. They can camouflage in complete darkness and even against man-made patterns.
14. Despite being colorblind, cuttlefish can match colors to their environment (theories include chromatic blur and Luka fors cells).
15. Cuttlefish use color-changing for communication, hunting, and "disco fighting" for territorial disputes.
**Mating and Life Cycle**
16. Males mate by inserting spermatophores into a sack below the female's mouth.
17. Females lay several hundred eggs after successful mating, which hatch after two months.
18. Female cuttlefish typically die shortly after laying eggs.
19. Newborn cuttlefish are miniature versions of adults, with no distinct immature stage.
**Intelligence and Problem-Solving**
20. Cuttlefish have been observed to have basic counting abilities (distinguishing between numbers like 1, 3, 4, and 5).