Blog Archive

Posted on October 25, 2010 by Greg Estes

Anyone interested in booking a tour with us please click on Greg’s trips Page or contact us at galapagos@gnhtours.com.

Greg photo7

NOVEMBER

A great time for observing giant tortoises on land, sea turtles in the water and for scuba diving at Wolf and Darwin Islands.

Giant Tortoises

The following video includes eruption footage, Lonesome George, and the evacuation of tortoises from the Cerro Azul eruption in 1998. (from Galapagos Suited for Survival by Greg Estes & Thalia Grant)

 

While most visitors to the islands get a chance to view giant tortoises in captivity, they don’t always see them in the wild. November, however, is a particularly good month to observe tortoises roaming in the highlands of Santa Cruz Island. At Primicias and Hacienda Mariposa, large numbers of tortoises are found within easy walking distance, and these properties are worth a visit. I recently talked with the owner of Hacienda Mariposa and he estimates there to be least 50 tortoises on his land at the moment. Although these tortoises are found on private property they are wild and move freely in and out of the National Park during the year. Between February and July most of the tortoises move back onto National Park land, where some can be seen at the tortoise reserve, El Chato.

Recent research on the genetics of the Giant Tortoises has given hope that the Pinta Island and Floreana Island tortoises may have a chance to come back. The Floreana tortoise disappeared in the mid 1800s, not long after Charles Darwin’s visit to the islands in 1835. The sole survivor of the Pinta Island tortoise is Lonesome George (the most famous animal in Galápagos) who now resides at the Charles Darwin Research Station on Santa Cruz Island. Attempts to breed George with tortoises from other islands have been unsuccessful. However, Pinta island tortoise DNA has now been found in tortoises on Wolf Volcano on Isabela Island. Why would Pinta Island tortoise DNA be on Isabela Island? It is believed that whalers sometimes took tortoises off one island and placed them on another, or that some tortoises were dumped overboard and then floated ashore, where they then hybridized with the resident tortoises. Plans are now being made to breed the Isabela-Pinta tortoises in captivity, with the goal of one day repopulating Pinta Island with their offspring.

Floreana Island DNA has also been found in some of the tortoises on Wolf Volcano, and a captive breeding population of these tortoises is also being planned. The Charles Darwin Foundation plans to restore Floreana Island with tortoises ..and also mockingbirds. The Floreana mockingbird is one of the rarest birds in Galápagos and currently only survives on two small islets near Floreana; Gardener and Champion. This mockingbird was one of the most important organisms Charles Darwin observed and collected on the Voyage of the Beagle, as it played a key part in convincing him of evolution.

Sea Turtles

The following video includes sea turtle nesting, ghost crab and hermit crabs, giant centipede and a turtle hatchling escaping from a marauding mockingbird (from Galapagos Suited for Survival by Greg Estes & Thalia Grant)

November is a good month to see sea turtles, as it marks the beginning of their mating season. From November through to April many sea turtles can be seen mating in coves near sandy beaches, where the females then lay their eggs. The hatchlings usually emerge in April and May.

Sea turtles can be seen throughout the archipelago but a particularly good site to observe them feeding underwater is on the western side of Isabela Island.

There is only one species of sea turtle which nests in the Galápagos Islands. At one time it was thought to be the same species as the Pacific green turtle (Chelonia mydas). It is now recognized as a distinct species and is called the black turtle, Chelonia agassizi. It is relatively successful compared with sea turtles found in other parts of the Pacific, as the human impact is lower in the Galápagos Islands. For example people who live in the Galápagos Islands do not dig up turtle eggs for making energizer drinks as they do in Central America. But there are concerns for the turtles on a number of the Galápagos islands where introduced predators are found.

When I first came to Galápagos in 1982 there were plans to put up a fence behind the beach at Playa Espumilla on Santiago Island because of the feral pigs devouring the turtle eggs. Fortunately the pigs have now been eradicated from Santiago but there are still problems with introduced rats. Although the turtles are protected within the marine reserve they do venture outside the reserve, where they are vulnerable to human activities. A turtle which had been tagged in Galápagos was recently found in a tuna longline near Panama.

Diving at Darwin and Wolf

The following video includes schools of hammerhead sharks at Wolf Island and a whale shark and silky shark at Darwin Island, (from Galapagos Suited for Survival by Greg Estes & Thalia Grant)

November is usually great for scuba diving at Darwin and Wolf Islands. Schools of hundreds of scalloped hammerhead sharks can be observed and it is a good time to look for whale sharks (the world’s biggest fish), which can get up to 60 feet long. Dolphins and large moray eels are also a common sight and there is always an abundance of reef fish and pelagic fish.

Hammerheads gather in big schools at Darwin and Wolf during the day, and often go out into the open water to feed at night. It is thought they feed on pelagic squid. Most of the hammerheads schooling at Darwin and Wolf appear to be females, with males mainly found at the periphery. Their behaviour of schooling around Darwin and Wolf could be related to either mating or cleaning. Males have been observed darting into the school to mate with a female. The alluring King Angelfish is one of a number of species of reef fish which groom the sharks.

Hammerheads tagged in the Galápagos have been found moving outside of the archipelago. It appears that they move between the islands of Malpelo (Colombia), Cocos (Costa Rica) and Galápagos. One hammerhead shark that was tracked was found to have traveled over 400 miles in less than two weeks between Galápagos and Cocos Island.

 

Tsunami in the Galapagos Islands

Posted by Greg Estes on February 27, 2010 (click here for Reuters article on tsunami alert in Galapagos)

“This morning I received  a skype call here in Puerto Ayora, Galapagos. It was a family member calling with a warning that a tsunami may be on its way to Galapagos and many people here were making their way to higher ground as a precaution. After checking the web for the latest from NOAA I opted to stay in Puerto Ayora and keep checking  the news. I did go to the top of my house where I have a view of both Academy Bay and the back bay in Puerto Ayora.  I was there between 7:30 to 8:45 am and observed a rapid (every 5 to 10 minutes) ebb and flow of 3-5  feet of sea water into both bays. The biggest surge came at 7:55 am. There is one little island in the back bay which at one moment was connected to Santa Cruz island by the tide dropping and then within minutes became an island again as the water surged back in. There was debris in the bay. Many of the tour boats had weighed anchored and were waiting out the tsunami in deep water offshore. There was one report of a tour boat touching the bottom of the bay and heeling to one side before the tide came back in and brought her back upright. I have been in contact with people who have evacuated to higher ground. Although the tsunami warning has been lifted people in the highlands apparently are being kept away from Puerto Ayora until Saturday afternoon as a safety precaution.”  (click here for tsunami bulletin from NOAA)

Galapagos Sea Lions Cooperatively Feeding

Posted by Greg Estes on February 6, 2010

“On a recent trip in Galapagos I was asked by a biology student whether sea lions in Galapagos cooperatively feed. I had heard of marine mammals cooperatively feeding (for example bottle-nosed dolphin, humpback whales and orcas) but I couldn’t remember seeing sea lions cooperatively feed. In fact it is rare to see sea lions feed in Galapagos. I have observed sea lions on the surface of the sea ripping off pieces of flesh from large fish and octopus. And I have also observed individuals catching fish as they dash repeatedly through a school of small fish. But I had never seen this as a cooperative behavior. But later on that same trip I came across several males at Puerto Egas on Santiago Island which appeared to be trapping a group of fish by herding them into a submarine grotto. I managed to get a short clip of video which I have uploaded onto YouTube

One of the sea lions objected to my presence as he most likely considered me a competitor. If you look closely at the video you can see him make a dash towards the camera. At that point I decided it was time to give him some space.”

The following is a comment by Greg posted on February 6, 2010 in response to a National Geographic video entitled Welcome to the Galapagos Islands


“Great footage and message about taking care of the Galapagos marine environment. But there are a number of mistakes made in the narration regarding Charles Darwin.

First of all Darwin didn’t record seeing penguins, fur seals or flightless cormorants. The flightless cormorant did not feature in his thinking on evolution and was never mentioned by Darwin.

Secondly, although Darwin didn’t dive below the sea he was interested in the marine environment. He was the first to collect specimens of fish in the Galapagos. He also collected marine invertebrates.

Thirdly, there were people living in the Galapagos when Darwin made his visit. There were people living on both Floreana and Santiago Islands and Darwin met them. In fact meeting these people was particularly important to Darwin as they were able to tell him about the different types of tortoises found on the different islands.

Check out the book Darwin in Galapagos: Footsteps to a New World for a completely new and comprehensive account of Darwin’s visit to the islands. The authors have retraced Darwin’s steps using his original manuscripts and for the first time have been able to clarify what Darwin observed in the islands and what was key to his understanding of evolution.”

 

The following is a comment by Greg posted on February 3, 2010 in the New York Times in response to Olivia Judson’s article entitled Fearless which appeared February 2, 2010 (click here to view article)

“The reason that these islands were not settled is not because of luck but because there is very little fresh water in Galapagos. FitzRoy, the captain of the Beagle, had to put the crew on rations because he couldn’t find a good place to resupply the ship with water. Eventually he was forced into resupplying at San Cristobal island, where the sea was rough, as this was the only place where he could find sufficient water for the ship. Geologically the islands are similar to the Hawaiian islands but a big difference is there are no lush islands with waterfalls in the Galapagos. The Hawaiian islands were colonized by people long before the Galapagos and that accounts for why so many of the native birds have gone extinct in Hawaii. There has not been a single species of bird going extinct in Galapagos. This can be attributed largely due to the scarcity of fresh water making it difficult for people to colonize the islands. In 1937 there were only 34 people living on Santa Cruz island which now has the largest human population in the Galapagos estimated to be between 20 – 30,000.

On one of the islands (South Plaza) in Galapagos one finds land iguanas which are fearless at a visiting site. But they haven’t always been that way. Back in the 1950’s people were still hunting land iguanas for food (Darwin himself ate land iguanas while in the Galapagos in 1835). It was very difficult to find iguanas on South Plaza in the 50’s because as soon as visitors appeared the iguanas were so skittish they would scamper for cover. When tourism began in the 1960’s it was not so well regulated as it is now. Today there are strict National Park regulations which limit what visitors are allowed to do at the visiting sites. For example you are not allowed to feed the animals. In the 60’s visitors would bring food ashore to feed the iguanas. Within a decade of being hunted the iguanas were displaying the opposite behavior towards people where they would run down to the landing when visitors arrived.

Loss of flight in the Flightless Cormorant was not about being blown out to sea. The Flightless Cormorant is a seabird. It is thought the evolution to flightlessness with the Flightless Cormorant was not only due to a lack of land mammal predators but also the abundance of food inshore due to the upwelling of nutrient rich water from the Cromwell current which bathes the islands of Fernandina and Isabela where the Flightless Cormorant is endemic. The Flightless Cormorant didn’t need to fly long distances to find food. Also by putting the energy for wing development into their legs and feet they were able to dive down deeper, using their feet, to occupy a niche which other birds could not reach. The Flightless Cormorant did not feature in Darwin’s thinking on evolution as it was not described until after he died. He never commented on the Flightless Cormorant.

The Galapagos Islands has the coldest water on the equator anywhere in the world. I have been diving in 56 F at one of the dive sites which has been dubbed the icebox by the dive guides. This may account for why the marine iguanas were so quick to swim back ashore when being tossed in by Darwin rather than the fear of predators. Marine iguanas typically feed under the water in the middle of the day after their body temperature has heated up.

As far as Darwin and Galapagos being an old story with nothing new, nothing could be further from the truth. Check out the book Darwin in Galapagos: Footsteps to a New World for a completely new and comprehensive account of Darwin’s visit to the islands. The authors have retraced Darwin’s steps using his original manuscripts and for the first time have been able to clarify what Darwin observed in the islands and what was key to his understanding of evolution.”