Date: February 20, 2022
After leaving Isla Solarte we visited another of the larger islands of Bocas del Toro: Isla Colón. This is the island where the main town, Bocas Town, is situated. Bocas Town is at the southern tip of Isla Colón but we went further north and anchored off Starfish Beach. The beach is so named because the sandy bottom off the beach is full of large starfish. However, we mostly noticed the beach because every morning an armada of small motor boats would bring out tourists and locals from town and from nearby resorts and deposit them on the beach where a couple of bars would play music all day long and lots of water motor activities would take place. Then at 6 pm all the boats and people would leave and calm was restored. We went on a dinghy excursion ashore to see some of Isla Colón by foot.
Bjarne had found an unpaved road running along a residential area on the Northwest coast on Isla Colón. We walked there for a couple of hours and saw no cars and only a few people on foot or on bikes. We saw lots of lush jungle trees and plants:
We saw a small snake crossing the road:
We also found a couple of the Isla Colón variant of the Strawberry Poison Dart Frog — Yellow-green base color with irregular brown spots:
Here is a smaller specimen of the species that usually measures only 1.7-2.5 cm when fully grown:
Some of the other color variants that can be encountered in the Bocas del Toro area are:
Almirante peninsula: red or orange body with dark blue/grey legs
Kusapín peninsula and Escudo de Varaguas: red back with blue sides and belly
Isla Popa: yellow-green back and a blueish pale on the sides and belly, sometimes dark spots on the legs and on the back
Isla San Cristobal: red base color with all four legs blue, with or without black dots
Tierra Oscura peninsula: blue back and cobalt blue belly, with or without a few small black spots
Isla Bastimentos: orange to red back and white belly, dark spots and splotches
Isla Loma Partida: greenish blue with small black speckles on the back and legs
It's really amazing that the same species of frog can show such diverse color variations. But that's not the only interesting thing about the Strawberry Poison Dart frog (Latin name: Oophaga pumilio): As the name implies the skin of the frogs is poisonous but the poison is not something the frog synthesizes itself but rather it obtains the poison through its diet. It eats particular subspecies of mites and/or ants that contain the alkaloid toxin Pumiliotoxin 251D. The frog itself is not affected by the poison but incorporates and accumulates the poison and can later release it from glands in its skin if it feels threatened. The toxin has a repressive effect on cardiac function and organisms preying on the frogs experience convulsions, paralysis, and death. Frogs that live in captivity and eat other species of insects or mites lose the ability to excrete poison on their skin.
These frogs exhibit a high degree of parental care compared to other amphibians: After the eggs have been laid in a small reservoir of water, the male protects and waters the nest. After 10-12 days, the eggs hatch and the female transports the tadpoles on her back to some other water-filled locations where the tadpoles are deposited one at each location. Then the female will come back to each tadpole every few days and deposit several unfertilized eggs for the tadpole to feed on. The unfertilized eggs contains some of the alkaloid toxin that the female has accumulated through her diet of mites or ants and thus the toxin is passed on to the tadpole giving them early protection against predators. The feeding goes on for about a month after which the tadpole will metamorphose into a small froglet.
Towards the end of our hike we found a smaller trail leading to the coast:
...and found this:
A perfect and deserted sliver of a beach with driftwood and palm trees:
From the beach we could see the small Isla Pajaros (Bird Island), a tiny rocky island that is home to thousands of birds: