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Day 5

Our final day of excursions started with the shorter hike to the Sierra Negra caldera, which is one of the largest active calderas at nearly 10 km diameter. We walked into the caldera and the sulphur mines, where there were some pockets where you could hold your hand over and feel the heat radiating (surely just fine for our health to be radiated for a second). Inside the vents, it is about 300 degrees Celsius (~575 Fahrenheit). We could also see the sulfur gas coming out of the largest vent (from a safe distance, of course).

Hiking La Sierra Negra Caldera Sulfur Mines
Drive to the caldera
View of the caldera
At the top
Panorama of the caldera
Incredible to see the changing landscape and flora as we hiked
Walking through the caldera to the sulfur mines
Sulfur mines
Pahoehoe lava rocks
Sulfur vent about the size of our hands. It's about 300 degrees celsius inside the vents
Large sulfur vent
Another large sulfur crater - we had to be careful not to stand directly in front of it due to the heat
A visitor

We visited a lava cave, formed by flowing magma from an eruption, after seeing the caldera. The cave was surrounded by avocado trees, which are invasive to the area and are in the process of being removed and replaced with native species. We could see the roots of the avocado trees growing into the cave.

Lava Cave on Isabela Island

We had about 1 hour between excursions and took the opportunity to finally visit the flamingo lagoon, which was nearby our hotel. We were completely spoiled by our opportunities to be close to wildlife that we were disappointed by the raised path and barriers to seeing the flamingos closer. That said, it was still incredible to see flamingos in a natural habitat where they can come and go as they please. We heard from others on our tours that if you have the opportunity to visit more than once, you start to get a sense of their patterns traveling to different parts of the lagoon.

Visiting the Flamingo Lagoon
Entering the lagoon

Our final excursion of the trip was a land and snorkeling tour of las tintoreras, which are land formations and canals made from lava flow named for the white-tipped reef sharks who take residence to nap in the canals. Apparently the sharks sleep there for the heat they can feel from the magma below. We had the joy of seeing more blue-footed boobies, eagle rays, and the sole Galápagos penguin residing on Isabela Island at the time we were there. On the land tour, we saw a marine iguana nesting ground and groups of sleeping white tipped reef sharks.

Hiking Las Tintoreras
A fever of eagle rays as we arrived
A fever of eagle rays as we left the pier
Always excited to see more boobies
Pelican on the rocks
Sea lion swimming
The sole Galápagos penguin on Isabela Island this time of year. He was stranded and hunts by himself and on the rocks taking a rare break.
Sea lion pup coming to say hi
Sleepy baby
Sleepy papa
Marine iguana on the lava rocks
Marine iguanas everywhere
The tintoreras are named for the white tipped reef shark.
White tipped reef sharks sleeping on the ocean floor along the canals. They get cleaned by other fish while they nap.
Marine iguanas don't swim and hunt on their own until they're 5 years old. The tintoreras serve as a nesting and mating ground.

Today’s tour concluded with snorkeling las tintoreras. This was our most challenging snorkeling experience of the trip, likely as much because we were already tired from our hike and days of adventuring leading up to it as it was due to the more challenging currents. It was well worth it to swim with sea turtles, eagle rays, and to catch sight of many blue starfish.