Edit Blog Post
Published: October 6th 2017
Today's activities included visits to Santiago (San Salvador, James) Island at Puerto Egas and then on to the much-anticipated visit to the Natural Habitat Adventures leased private "campsite" on Santa Cruz (Indefatigable) Island.
At Puerto Egas we got our first close looks at the Galápagos fur seals. Despite the name, these are actually sea lions. Their fur is thicker than that of the Galápagos sea lions, and thus was more valuable as a pelt to sell. Extensive hunting nearly exterminated these animals in the late 1800's and early 1900's. Their numbers rebounded once hunting was halted, but declined again following the severe El Niño of 1982-1983. This species is more vulnerable to climate variations due to the longer time the mother cares for the pups. The pups are largely dependent on the mother's milk for 18 months, and may continue to suckle for 2-3 years. A new pup born during that time must compete for a finite resource. In times of abundant food, 95% survive, but in times of food scarcity many die. Practically all the pups died during the severe El Niño and up to 30% of the adult population. Numbers have rebounded again, and it is estimated that
there are currently about 40,000 animals. They are endemic to the Galápagos islands, but there is a small colony in northern Peru. Puerto Egas is a landscape of dramatic lava, and at first landing we were automatically drawn to a large rock window on the coast. Landing was delayed for a few minutes. Directly in front of the boat a couple of sharks were thrashing about in the shallow water catching fish. They were nearly grounding themselves.
We were very fortunate on this trip in having the senior veterinarian for the Houston Zoo on board. He is a real authority on the tortoises and has been intimately involved in the attempts to re-establish genetically pure populations and to eradicate introduced species that have decimated indigenous populations, such as rats, cats, pigs, and goats. Almost nightly he gave us lectures on various aspects of his work (the talk about doing phallectomies on male tortoises of indistinct genetics was a real show-stopper). He described the highly successful goat eradication programs, using mata hari goats after the major populations have been killed off. Female goats only attract males when they are in estrus, which is eliminated when they are sterilized, so they
put in IUD's which actually put the females into near-continuous estrus. They have radiolocation collars, so after they have been left to wander around for a while, hunters in helicopters go up and find them and kill any goats hanging around. Pigs are also killed by shooting. Rats are a little more complicated. On most of the islands, they were able to put out bait containing rat poison. Unexpectedly, both the tortoises and the rats ate the bait, but tortoises apparently are nearly immune to the anticoagulant effects of the poison. Hawks are not, and early one some died from eating the poisoned rats, but now they can capture a breeding population of hawks if necessary and re-introduce them when the rats are gone. All of this gets more difficult in the case of islands such as Fernandina, Santa Fe, and Santiago, where there are populations of indigenous and endemic rice rats. I don't think they have figured out what to do there. Cats probably represent the most difficult introduced predators to control, and I don't think they have found a solution for that problem.
With the informative lectures, we were very much looking forward to seeing the giant
tortoises, and therefore there was much anticipation in advance of the trip to the tortoise habitat. We had to anchor a fair way out from the harbor at Puerto Ayora because of shallow water, and it was a long panga ride to shore. We boarded a bus and drove up into the highlands. Most of the Galápagos tortoises live in upland areas where grasses are plentiful. What I had not considered prior to this trip was the ecological role of tortoises. In the islands, they are the large herbivores (think cows). They feed on the grasses that grow in lush profusion in the upland areas (at least the one we visited). On the way up to the habitat, we stopped at one of two large sunken magma craters that bracket the road. They were described to us as sinkholes, but they are actually the old volcanic craters that collapsed when the magma drained away. The crater is forested with Scalesia trees, actually a member of the Asteraceae family. They only grow in the sun, so a forest of them grows up, and at some point they all die and a new forest of seedlings comes up. Never thought I would
see a forest of 60 foot tall daisies.
The habitat is near the summit of the island, and consists of a lush grassy meadow area in a dense cloud forest. Rain is more common here than in the lowlands, but moisture comes from largely from the garua mist/drizzle. Everything in the area is extremely green and lush. The habitat where we would spend the night consists of a central building where there are cooking facilities and a small bar and a place to eat, and further out a series of elevated "treehouses" and quarters on the ground. These are like the permanent tents we saw in Africa, with wooden floors and en suite bath facilities. Immediately after arrival, we all headed out into the meadow to observe the numerous large tortoises that were evident. They move slowly ahead mowing down the grass in front of them. When night comes, they just withdraw into their shells to sleep during the dark hours. The tortoise population here is not captive, free to come and go as they will. We had a drink, ate a delicious supper, and retired to our less confining cabins. One thing I have not talked about is
that most of the people in our group were from Houston, and were out of touch as Houston was being drowned by Hurricane Harvey. There was some minimal internet connectivity here, and they were able to find out something about their houses etc in some cases. Glad I was not in that situation.
Tot: 0.155s; Tpl: 0.021s; cc: 14; qc: 33; dbt: 0.0119s; 1; m:saturn w:www (220.127.116.11); sld: 1;
; mem: 1.3mb