Giant clams, known scientifically as Tridacna maxima, can reach impressive sizes of up to 4.5 feet and weigh over 700 pounds, making them vital components of tropical coral reef ecosystems.

A recent study from CU Boulder, published on January 4, 2025, in Communications Biology, sequenced the genome of T. maxima, uncovering genetic adaptations that enable these clams to thrive alongside algae.

The research revealed that T. maxima has evolved specific genes to identify beneficial algae while simultaneously downregulating immune genes, allowing them to tolerate the long-term presence of these organisms.

Interestingly, the study also found that giant clams possess fewer genes associated with body weight control, which may explain their remarkable ability to grow to such large sizes.

In terms of conservation status, the International Union for Conservation of Nature (IUCN) recently updated its assessment, declaring T. gigas as critically endangered, while T. maxima remains classified as least concern due to its widespread distribution.

However, giant clams are facing significant threats from climate change, particularly as rising ocean temperatures can lead to the expulsion of their symbiotic algae, resulting in starvation.

Moreover, genetic similarities among different giant clam species may obscure their individual conservation needs, prompting experts to call for more genetic studies to accurately assess these threats.

Contrary to popular myths, giant clams do not eat humans; they are actually herbivorous, relying on algae for their sustenance.

This reliance on algae is part of a symbiotic relationship known as photosymbiosis, where the algae produce nutrients through photosynthesis while the clams provide protection and essential nutrients.

Protecting giant clams is crucial not only for their survival but also for maintaining the health of coral reefs and supporting marine biodiversity, as they offer shelter and food for various marine organisms.

The findings from the CU Boulder study underscore the importance of giant clams as keystone species in marine ecosystems, highlighting their role in sustaining biodiversity.