Category: GALAPAGOS ISLANDS May 2011


Prionurus laticlavius   Family Acanthuridae

DISTRIBUTION:  Eastern Central Pacific: Gulf of California to El Salvador, including the Revillagigedo and Galápagos Islands.

HABITAT: Reef-associated; marine; depth range 5 – 35 m in shallow warm tropical waters with young often in tidepools.

APPEARANCE: Maxium length to 60 cm.  Grey in color  with a yellow tail and two vertical black bands on the head divided by a whitish band.  They have three scalpel like plates on each side of the tail.  Very similar to Prionurus punctatus  but lacks total body spots.

DIET: Plankton

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Tropidurus spp.   Family Tropiduridae

DISTRIBUTION: The seven different species are T. grayi, T. bivattatus, T. pacificus, T. habellii, T. delanonis, T. albemarlensis, and T. duncanensis  but only one species is found per Island.

HABITAT:  Lizards begin each day basking on the warm rocks for about an hour depending on the sun’s heat.

 APPEARANCE:  The male is larger than the female growing to about 10 inches (25cm).  Females have a bright orange throat extending up to cover some of the face.  The male is pale tan, darker along the sides, and mottled with black speckles.  There is much variability among species and even with the same species.

FEMALE LAVA LIZARD (below)

REPRODUCTION:  Male lizards will mate with all females passing through their territory. Females will dig deep in the soil to lay their eggs to protect them. The period of incubation takes about 3 months (similar to Iguanas) before the young lizards born measuring about 2 inches long at birth.

REMARKS: They are eaten by hawks, snakes, mockingbirds, herons, and centipedes.  Besides camouflage, they have one major defense mechanism to help keep them from joining the food chain, by being eaten by a higher animal: they will “drop” their tail when a predator grabs hold of it. The dropped piece of tail will continue to move about while the lizard attempts to flee and will regrow slowly.

LAVA LIZARD regrowing tail.

REMARKS: One often sees male and female lava lizards doing “pushups”  defending their territory or while courting.

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VIDEO LINK: Galápagos Series  http://www.youtube.com/watch v=VySe1X12gqs&hd=1


Conolophus subcristatus                 Iguanidae family

HABITAT: Arid low altitude portions of the islands.

 APPEARANCE: Iguanas have distinctive eyelids, external eardrums, dewlaps (throat pouches), each limb has 5 toes with sharp claws allowing them to climb.  Charles Darwin described the Galapagos Land Iguana as “ugly animals, of a yellowish orange beneath, and of a brownish-red color above: from their low facial angle they have a singularly stupid appearance”.

C.subcristatus   grows  to approximately 3 ft (1 m) in length and weigh up to 25 pounds.

DIET: The mainstay of its diet is the prickly pear cactus. They eat the pads and fruit including the spines. The cactus provides both food and water for the land iguana, making it possible to survive without fresh water for a year.  C. subcristatus  are also opportunistic carnivores supplementing their diet with insects, centipedes and carrion.

REMARKS: Part of the adaptation to the drier environment includes a conservation of energy by slow movement. This makes the animals seem lazy or stupid. Land iguanas burrow into the ground creating tunnels which provides a place for nesting, shade during the day and protection at night.

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VIDEO LINK   http://www.youtube.com/watch?v=VySe1X12gqs&hd=1

Amblyrhynchus cristatus    (Iguanidae)

 DISTRIBUTION: Found only on the Galápagos Islands. It has spread to all the islands in the archipelago.

HABITAT: has the ability, unique among modern lizards, to live and forage in the sea, making it a marine reptile. A. cristatus can dive over 30 ft (10 m) into the water. It mainly lives on the rocky Galapagos shore, but can also be spotted in marshes and mangrove beaches.

APPEARANCE: Not always black; the young have a lighter coloured dorsal stripe, and some adult specimens are grey. The iguanas living on the islands of Fernandina and Isabela are the largest found anywhere in the Galápagos. On the other end of the spectrum, the smallest iguanas are found on the island on Genovesa. Adult males are up to 1.7 metres (5.6 ft) long, females 0.6–1 metre (2.0–3.3 ft), males weigh up to 1.5 kilograms (3.3 lb). its laterally flattened tail and spiky dorsal fins allow it to swim further and faster, while its long, sharp claws allow it to hold onto rocks and other materials around it when there are strong currents so that it doesn’t drown or get lost/too far away from land.

DIET: The marine iguana feed almost exclusively on marine algae. Larger members of the species feed more often by diving at high tide while smaller animals are restricted to intertidal feeding at low tide.

REPRODUCTION: Males defend mating territories during the three-month annual breeding season. Females lay one to six eggs in burrows dug 30 to 80 cm deep. The eggs are laid in sand or volcanic ash up to 300m or more inland. Females guard the burrow for several days then leave the eggs to finish incubation, which is approximately 95 days. Nesting months are January through April depending on the island.

REMARKS:  As an ectothermic animal,  A. cristatus can spend only a limited time in the cold sea, where it dives for algae.  However, by swimming only in the shallow waters around the island they are able to survive single dives of up to half an hour at depths of more than 15 m.   After these dives, they return to their territory to bask in the sun and warm up again.

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VIDEO LINK   http://www.youtube.com/watch?v=VySe1X12gqs&hd=1

Geochelone nigra  (Testudinidae)

REPRODUCTION AND BREEDING

MATING: Galápagos Tortoises mate by internal fertilization from December to May with the females laying eggs from June through November in the arid zone at lower elevations.

INCUBATION: The eggs are collected by Park rangers and incubated at breeding centers in the Galápagos (Isabela and Santa Cruz) Islands.

They are put in the same position in which they were found so as not to harm the embryo. Incubation takes 90-120 days with temps. less than 83〫F  producing males and higher producing females.

NEWBORNS:  Newborns are kept in terrariums for the first two years of their life to protect them from predators such as rats and cats.

ADAPTATION PENS:  The young turtles aged 2-6 years old are kept in a protective area with food and water similar to the wild where they will be released.  When they reach 20-25 cm long they are released into the wild.  They are identified while in captivity by color-coated paint to show their Islands of origin individual ID number.

SEX: Until they are 12-20 years sex cannot be visually differentiated.  The adult males have a much longer tail and are usually larger than the females.

ADULTS: Grow to up to 600 pounds (270kg) and females to about 110 pounds (50kg). Shells average just over a yard in length.  Isabella has about 6000 tortoises the most of any Island.  Adults can live to 170 years in captivity.

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VIDEO LINK   http://www.youtube.com/watch?v=VySe1X12gqs&hd=1

Geochelone nigra (Testudinidae)

Distribution: Native the Galápagos Islands.

Habitat: On islands with  dry lowlands, the tortoises are smaller, with saddleback shells and long necks. Domed tortoises live at higher altitudes in thick shrubbery which is also their food.

Appearance: A longer neck and legs with a saddle shaped shell help this tortoise reach shrubs and cactus branches beyond its reach.

Diet: Primarily tree like cactus of the genus Opuntia.

Remarks: Smaller body size allows for more rapid cooling than the larger Domed race which live at higher altitudes where it is cooler.

California Academy of Sciences Specimen collected during the 1905-06 expedition.

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VIDEO LINK   http://www.youtube.com/watch?v=VySe1X12gqs&hd=1

Geochelone nigra  (Testudinidae)

Remarks: There are 14 described subspecies of the Galápagos tortoise of which 11 still exist, some with only small populations. There are “dome-shelled” and “saddle-backed” tortoises.

Distribution:  Native to seven of the Galápagos Islands. Habitat: On islands with humid highlands, the tortoises are larger, with domed shells and short necks. On islands with dry lowlands, the tortoises are smaller, with saddleback shells and long necks. Habitat: Domed tortoises live at higher altitudes in thick shrubbery which is also their food.

Appearance: They have a large bony shell (carapace) of a dull brown color. The plates of the carapace are fused with the ribs in a rigid protective structure that is integral to the skeleton. Lichens can grow on the shells of the slow-moving animals. Tortoises keep a characteristic scute (shell segment) pattern on their shell throughout life, though the annual growth bands are not useful for determining age, because the outer layers are worn off with time. A tortoise can withdraw its head, neck and forelimbs into its shell for protection. The legs are large, stumpy, with dry scaly skin and hard scales. The front legs are five-clawed, and the back legs are four-clawed.

Diet: The Galápagos tortoise is a generalized herbivore feeding on grasses, vines, cactus fruit, and other vegetation. It eats the fruit of the manzanello tree and fallen fruits and spiny pads of the prickly pear.

Remarks: A slow metabolism and large internal stores of water mean they can survive up to a year without eating or drinking. Spanish sailors who discovered the archipelago in 1535 actually named it after the abundant tortoises; the Spanish word for tortoise is galápago.

California Academy of Sciences Specimen

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VIDEO LINK   http://www.youtube.com/watch?v=VySe1X12gqs&hd=1 

Chelonis mydas agassisi  (Cheloniidae)  

Distribution:  World wide but turtles from the Galápagos population have been found along the shores of South and Central America.

Habitat: Marine surface dwellers with adults commonly inhabiting shallow lagoons.

Appearance: Size up to 300 pounds (135kg) with adults growing to 1.5 metres (5 ft) long..  Colors are variable; green, brown and black.  Their common name derives from the usually green fat found beneath their carapace (upper shell).  It has a dorsoventrally flattened body covered by a large, teardrop-shaped carapace and a pair of large, paddle-like flippers. It is usually lightly colored, although parts of the carapace can be almost black in the eastern Pacific.

Diet: In the Galapágos mainly algae.  World wide sea grass and jellyfish.

Reproduction:  Like other sea turtles, they migrate long distances between feeding grounds and hatching beaches. Many islands worldwide are known as Turtle Island due to green sea turtles nesting on their beaches. Females crawl out on beaches, dig nests and lay eggs during the night. Later, hatchlings emerge and walk into the water. Those that reach maturity may live to age 80 in the wild.

VIDEO LINK   http://www.youtube.com/watch?v=VySe1X12gqs&hd=1

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California Sea Lion sub species.     Zalophus californians wollebacki

Galápagos sea Lion  (Otariidae)      Arctocephus galapagoensis 

Distribution: Galápagos Islands.

Habitat: They spend a lot of their time swimming in the ocean but while on land they prefer sandy beaches and flat rocky areas that have plenty of shade and tidal pools. While at sea they will rarely venture further than 16 Kms (10 miles) from the coast.

Appearance: Descriptions will be for A. galapagoensis which are similar to Z. californians wollebacki  except the are smaller by about 100 pounds as adults.  Males are colored brown, females tend to be a lighter tan and juveniles are colored chestnut brown. Their bodies are streamline and they have well developed fore flippers which they use to propel themselves through the water. They can control their hind flippers independently which enables them to move around more effectively on land.  When males reach puberty they begin to develop a raised forehead and sometimes their hair is lighter coloured on their crest.  Length 150 – 250 cms (59 – 98 inches).  Weight 50 – 400 Kgs (110 – 880 lbs)

Diet: Fish, squid, octopus and crustaceans.

Predators: The main predators of Galapagos Sea Lions are sharks and killer whales. Dogs are also known to prey upon pups.

Reproduction: Breed between May and January and mating usually occurs in the water. Males hold their territories for 10 days – 3 months and during this time they aggressively defend it.   After a gestation period of approximately 9 months, females give birth to 1 pup. When the pups are born they weigh approximately 6 Kgs (13.2 lbs) and they are approximately 75 cms (29.5 inches) long.  When the pups reach 1 – 2 weeks old they will venture into the water and start to learn how to swim. They are weaned when they reach 11 – 12 months.

Remarks;  Galápagos Sea Lions are inquisitive and playful yet aggressive at times.  They are attractive and endearing but also lazy as they lie on beaches replenishing their oxygen.  They may be seen body surfing the waves and always seem to be playing with something including each other, iguanas, penguins, crabs or just a piece of seaweed.

VIDEO LINK   http://www.youtube.com/watch?v=VySe1X12gqs&hd=1

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Ghost Crab                                                    Ocypode sp.

Distribution: Galapágos Islands.

Habitat: Sandy beaches of fine volcanic rubble. The Ghost Crab tunnels down four feet into the ground at a 45 degree angle, creating 1-2 inch wide holes, which speckle the beach. At dusk, these crabs will sprint to the ocean in order to obtain oxygen from the water which washes over their gills.

Appearance:  Pale cream colored and elegant looking. The most distinctive feature of this ultra-fast little crustacean are his eyes which are at the end of a long retractable stalk.

Diet: Dead animals and debris they are also predators. If they can subdue it, they will eat it—including hatching sea turtles.

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