The order Sirenia gets its name from the association of species in this order with the mermaids of ancient mythology, with which ancient navigators often confused these animals. The confusion arose because when sirenians emerged to breathe, their appearance wrapped in algae that grow on their backs, referred to the hypothetical shape of a mermaid's hair and tail. This order is made up of two main families: Dugongidae and Trichechidae. Within the Trichechidae family, we have a single genus: Trichechus and three distinct species: The West Indian manatee (Trichechus manatus), the African manatee (Trichechus senegalensis) and the Amazonian manatee (Trichechus inunguis). The latter is the smallest and only one restricted to freshwater environments in the Amazon Basin, which we'll talk about today.
The Amazonian manatee is known for the absence of nails on its pectoral fins, which gives it the scientific name "inunguis": "without nails". In addition, the species has distinctive white spots on its ventral region, which function like a fingerprint and are unique to each individual. These herbivorous mammals are fundamental to the local ecosystem and are found mainly in calmer environments with an abundance of aquatic plants, such as water lettuce. The species can weigh up to 450 kg, move slowly in surface areas of rivers and have a low reproductive rate, giving birth to only one offspring per pregnancy every two and a half to three years. These characteristics make them particularly vulnerable to human activities such as fishing, boat accidents and illegal logging. In addition, cases of orphaned offspring resulting from anthropogenic actions are quite common. There are cases, for example, where the mother is captured, while the cub - still dependent on her care - is left completely helpless and often has a tragic end. The lack of parental care is serious, given that the cub is breastfed until it is about two years old.
The Amazonian manatee is classified as vulnerable by the International Union for Conservation of Nature (IUCN), so conservation activities for the species are essential for maintaining the ecological balance of its populations and the Amazon biome. As well as contributing to the fertility of aquatic ecosystems through their nutrient-rich feces, these animals help to control the overgrowth of aquatic plants, allowing light into the water and benefiting other species that depend on photosynthesis, for example.
Understanding the history and biology of these animals is crucial to knowing their importance on our planet. There are projects dedicated to this purpose and to caring for populations of these species, such as the Manatee Association (@associacaopeixeboi) and the NGO Friends of the Manatee (@ampa_peixeboi).
Author: Jordana Paiva - Creative Director of GEAS Brasil
Proofreading: Iago Junqueira - Partner of GEAS Brasil through the Wild Space Institute
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