Preceden

Evolution of Crocodilians Timeline

(Late Triassic, approximately 235 million years ago–Present)

This timeline traces crocodilian evolution from early archosaur relatives in the Triassic to the diverse modern species living today. Less

Go to: Timeline | Event List | Key Facts | Directory

Culture and media

Crocodile appears in the Rochester Bestiary

1280

The crocodile was described in the late-thirteenth-century Rochester Bestiary, which drew on classical sources including Pliny's Historia naturalis.

Crocodiles enter children's literature

1865 - 2008

Crocodilians became recurring characters in children's stories, including Lewis Carroll's poem How Doth the Little Crocodile in Alice's Adventures in Wonderland, Roald Dahl's The Enormous Crocodile in 1978, and Emily Gravett's The Odd Egg in 2008.

Image source: Crocodile

Crocodiles enter children's literature

The Elephant's Child acquires his trunk

1902

In Rudyard Kipling's 1902 Just So Stories, the Elephant's Child acquires his trunk after a crocodile pulls his nose very hard.

Image source: Just So Stories

The Elephant's Child acquires his trunk

Captain Hook loses his hand to a crocodile

1911

In J. M. Barrie's 1911 novel Peter and Wendy, Captain Hook loses his hand to a crocodile.

Crocodilians become horror-film monsters

1977 - 2007

Movies and shows often represented crocodilians as dangerous water obstacles or monstrous man-eaters, including Eaten Alive in 1977, Alligator in 1980, Lake Placid in 1999, Crocodile in 2000, and Primeval and Black Water in 2007.

Crocodile Dundee popularizes a crocodile nickname

1986

In the 1986 film Crocodile Dundee, the title character Mick Dundee's nickname is said to come from an incident involving a crocodile attack.

Conservation and trade

The gharial begins its chronic decline

1943

The gharial, historically widespread in India's major river systems, began a chronic decline in 1943.

American alligator recovery begins

1967

After its 1967 endangered-species listing, federal and state wildlife agencies in the southern United States worked toward recovery of the American alligator.

Image source: American alligator

American alligator recovery begins

American alligator is listed as endangered

1967

In 1967, the American alligator was listed as an endangered species, prompting conservation action by the United States Fish and Wildlife Service and state wildlife agencies in the southern United States.

Saltwater crocodiles receive legal protection

1971

Following severe population reductions from hunting, saltwater crocodiles in Australia were given legal protections.

Saltwater crocodile hunting reduces Northern Territory population

1971

In Australia, heavy hunting reduced saltwater crocodiles in the Northern Territory to five percent of their historical numbers by 1971.

Chinese alligator receives Class I protection

1972

In 1972, the Chinese government declared the Chinese alligator a Class I endangered species, granting it the maximum amount of legal protection.

CITES begins restricting crocodilian trade

1973

Starting in 1973, CITES attempted to prevent trade in body parts from endangered animals, including crocodile skins.

Captive breeding begins for Chinese alligators

1979

Beginning in 1979, captive-breeding programs were established in China and North America, creating a healthy captive population of Chinese alligators.

Lawfully hunted skins are defended at Botswana conference

1983

At the 1983 Conference of the Parties in Botswana, advocates for aggrieved local people argued that selling lawfully hunted crocodilian skins was reasonable.

Image source: CITES

Lawfully hunted skins are defended at Botswana conference

American alligator is removed from endangered list

1987

Legal protection and coordinated conservation allowed the American alligator to recuperate, and it was removed from the endangered species list in 1987.

Crocodilian skin trade expands under regulation

2000

By 2000, skins from twelve crocodilian species were traded by thirty countries. The skins were harvested legally in the wild or obtained from farms, while unlawful trade had almost vanished.

Saltwater crocodile numbers increase

2001

After legal protection was introduced, saltwater crocodile numbers in Australia had greatly increased by 2001.

Chinese alligators are reintroduced to Chongming Island

2008

In 2008, alligators bred at the Bronx Zoo were successfully reintroduced to Chongming Island in China.

Philippine crocodile reaches critically low numbers

2009

By 2009, hunting and destructive fishing practices had reduced the Philippine crocodile to around 100 individuals, making it possibly the most threatened crocodilian.

Classification and biology

Crocodylia receives its proper name

1968

Heinz Wermuth chose Crocodylia as the proper name for the group, basing it on the type genus Crocodylus, established by Laurenti in 1768.

Crocodilia encompasses broader relatives

1987

Before 1988, Crocodilia was used broadly for modern crocodilians as well as more distant relatives that are now classified within Crocodylomorpha and Pseudosuchia.

American alligator bite force is measured

2003

A study published in 2003 measured an American alligator's bite force at up to 2,125 lbf, or 9.45 kN.

Crocodilian respiration is found to be bird-like

2010 - 2013

Studies published in 2010 and 2013 concluded that crocodilians breathe more like birds than mammals, with airflow moving through the lungs in a unidirectional loop rather than tidally in and out.

Saltwater crocodile bite force is measured

2012

A 2012 study measured the bite force of a saltwater crocodile at 3,700 lbf, or 16 kN.

Basal reptiles are proposed to have vocal adaptations

2015

A 2015 discussion argued that species-specific morphologies in vocal folds or their analogues may reasonably be expected as far back as basal reptiles.

Image source: Crocodilia

Basal reptiles are proposed to have vocal adaptations

Modern crocodilian relationships are summarized

2021

A 2021 cladogram presented the relationships among the major extant crocodilian groups, providing a modern view of crocodilian evolutionary relationships.

Alligators fail a visual perspective-taking test

2023

A 2023 study using tinamou birds and American alligator test subjects found that the alligators did not appear to engage in visual perspective-taking like the birds.

Human interactions

Nile crocodile attacks are recorded

2010 - 2020

More than 1,000 attacks by Nile crocodiles were estimated to have occurred between 2010 and 2020, with almost 70 percent proving fatal.

Saltwater crocodile attacks are recorded

2010 - 2020

Saltwater crocodiles were implicated in more than 1,300 attacks on humans between 2010 and 2020, and almost half of those attacks were fatal.

American alligator attacks are recorded

2010 - 2020

American alligators were responsible for 127 recorded attacks between 2010 and 2020, only six of which were fatal.

Key Facts

  1. Crocodilians belong to Archosauria, the group that also includes dinosaurs, pterosaurs, and birds.
  2. Their early relatives, known as crocodylomorphs, appeared during the Late Triassic about 235 million years ago.
  3. Mesozoic crocodylomorphs occupied a wide range of habitats and included terrestrial, marine, and lightly built forms.
  4. Modern crocodilians include crocodiles, alligators, caimans, and gharials, with roughly 25 living species.
  5. Crocodilians are ectothermic reptiles and are the closest living relatives of birds.

Source

This Evolution of Crocodilians timeline was generated with the help of AI, using information found on the internet.

We work hard to keep these timelines accurate, but mistakes do get through. If you spot one, email us at [email protected] and we'll fix it for future visitors.

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