Why Are So Many of Fuvahmulah’s Tiger Sharks Female?

What the numbers show about Fuvahmulah's female tiger sharks

Imagine kneeling on the sand at Tiger Harbour and slowly counting the sharks that pass. Almost every big, striped body is a female. Why? The short answer: the site seems to work as a place where adult females spend their pregnancies, although researchers still cannot say exactly why they choose it.

The best numbers come from a long photo-identification study published in Scientific Reports in 2024. For about seven years, a research team photographed the tiger sharks of Fuvahmulah, recognised each one by its markings and measured them with lasers. They identified 239 individual sharks, and 84.5% were female. In real life, this means most of what divers see here are large juvenile and adult females, not a balanced mix of the species. You can read more about the species on our tiger shark Atlas page.

What the study does not tell us is where the missing males spend their lives, or where the females go between visits. It is a careful picture of one site, not of the whole Indian Ocean population.

A harbour full of pregnant sharks

The photo study also watched for pregnancy, judged from a clear swelling of the belly that lasted over time. From these observations, the authors concluded that adult females are likely to stay near Fuvahmulah while pregnant and to reproduce about every two years. The Important Shark and Ray Area factsheet for Fuvahmulah, based on the 2016 to 2023 data, notes that about a third of the adult females were seen going through at least one complete reproductive cycle.

A belly can be misleading, so the next step was to look inside. In May 2024, a team of scientists used a submersible high-definition ultrasound on wild, free-swimming tiger sharks at the site, and matched each shark to the island's photo-ID database. Of the 28 adult sharks they scanned, 26 carried embryos, or 93%. The embryos fell into two size groups, which suggests females at different stages of pregnancy. The authors describe the site as the first gestational ground identified for tiger sharks in the Central Indian Ocean. This is specialist scientific work done under permits, not something that happens on tourist dives.

How a tiger shark carries its young

Tiger sharks give birth to live pups instead of laying eggs, and the pregnancy is long. That is part of why a quiet place matters. A female carrying a litter for many months spends a big share of her adult life pregnant, and anything that adds stress or effort during that time has a real cost for her.

At Fuvahmulah, the photo study points to a cycle of roughly two years, with females disappearing for a while around the time they are thought to give birth. In other parts of the world, studies have suggested longer cycles, and the ultrasound team notes that the exact cycle for this species is still debated. So when someone tells you very confidently how often a tiger shark gives birth, it is fair to ask, "Where, and according to whom?"

So why so many females?

Here it matters to separate what is known from what is suggested. Each idea below is a hypothesis from the researchers, not a proven answer.

Sexual segregation. In many shark species, males and females, and small and large animals, live apart for parts of their lives. The Fuvahmulah team reads this female-dominated gathering as one more example, possibly linked to reproductive needs.

A safe place to be pregnant. The ultrasound study suggests the site may work as a refuge and gestation ground, where pregnant females can benefit from calm, warm water.

Reliable food. Fish waste from the tuna fishery is thrown out at the harbour, and the dive site is provisioned, so food is easy to find. The researchers suggest pregnant females may use these waters partly for the warmth and partly for this low-effort food. We look at what that food means in are Fuvahmulah's tiger sharks really wild if food is used.

What nobody knows yet is where the males spend their time, or where the females go to give birth. That honesty matters. The most interesting parts of this story are still open questions.

Why this matters for the island and for conservation

The IUCN Shark Specialist Group has recognised the waters of Fuvahmulah as an Important Shark and Ray Area. Tiger sharks qualify under its reproductive area criterion, based on photo-identification and observations of swollen bellies collected during scuba dives between 2016 and 2023. When so many pregnant animals use one small place, the way people behave there matters more than at an ordinary dive site.

The ethical side is not simple. The gathering exists partly because of fish waste and provisioning, and the sharks bring real income to a small island. The Fuvahmulah researchers recommend bringing all stakeholders' interests into local management plans that support sustainable ecotourism. We think the honest position is this: if you go, go as a quiet guest. No feeding by divers, no touching, no chasing, and no pressure on guides to "get closer" for a photo.

How to experience it respectfully

The Maldives Diving Regulation, under the Tourism Act, prohibits the feeding of sharks by divers. On top of this, shark diving codes of conduct were developed for Fuvahmulah with the local dive industry, local and national authorities and the Ocean Country Partnership Programme, including separate versions for divers and guides at Tiger Harbour. They set a minimum distance from the sharks and limits on group size and divers per guide, and they ask for no touching, chasing or harassing. Check the current version with your dive centre before you travel, because details can change.

This is guided scuba for certified, experienced divers, never a snorkel with tiger sharks. Heavily pregnant sharks deserve extra space. Never block a shark's path, stay low and still with your guide, and let each animal choose its own distance. Ask your dive centre what kind of exposure suit the local code recommends. A long-sleeved rash guard under your wetsuit also protects you from the sun on the boat ride. If you film, keep the camera small and your hands still. A compact action camera is easier to manage than a big rig, and it should never be a reason to move closer. A roll-top dry bag keeps your phone and papers dry on the boat. If you are curious about pregnancy, leave the checking to the scientists and simply enjoy watching from where you are.

Wildlife encounters are unpredictable. Diving with tiger sharks should always follow local regulations and experienced professional guidance.

If you would like to meet these ocean mothers with patience and space, begin with our Maldives Ocean Atlas, our guide on what scuba divers should know before a Fuvahmulah tiger shark dive and our Fuvahmulah page. If this made you curious about meeting the ocean in a slower way, you can explore our upcoming retreats.

Questions people ask

Are there male tiger sharks at Fuvahmulah at all?

Yes, but far fewer. In the long photo study, 84.5% of the 239 sharks identified were female, so males are only a small share of the sharks divers see.

Do the sharks give birth at Fuvahmulah?

There is no evidence of that. Females seem to leave around the time they are thought to give birth, and researchers say it is still unknown where the birth sites are.

How can scientists tell a shark is pregnant?

The long-term study used a lasting swelling of the belly over time, and a 2024 study confirmed pregnancies with an underwater ultrasound on free-swimming sharks: 26 of 28 adults scanned carried embryos. Divers should never try to get close to check.

How often do the females have pups?

The Fuvahmulah study suggests about every two years, but the exact cycle for tiger sharks is still debated, and other regions have reported different patterns.

Is Fuvahmulah officially recognised as important for sharks?

Yes. The IUCN Shark Specialist Group lists Fuvahmulah Atoll as an Important Shark and Ray Area, with tiger sharks qualifying under the reproductive area criterion.

Can divers feed the tiger sharks?

No. The Maldives Diving Regulation prohibits feeding sharks, and the local codes of conduct ask for no touching, chasing or harassing. Check the current rules with your dive centre before you travel.

Wildlife encounters are never guaranteed and never forced. Ocean Calling works only with vetted, ethical local operators, and every animal is free to approach, or not, entirely on its own terms.

Sources & further reading

1. Ocean Country Partnership Programme (JNCC) with the Fuvahmulah dive industry and Maldivian authorities. Codes of conduct for shark interactions, Maldives.
2. Ocean Country Partnership Programme (JNCC). Fuvahmulah shark diving review.
3. IUCN SSC Shark Specialist Group. Fuvahmulah Atoll Important Shark and Ray Area factsheet.
4. Vossgaetter, L. et al., 2024. Non-invasive methods characterise the world's largest tiger shark aggregation in Fuvahmulah, Maldives. Scientific Reports.
5. Sulikowski, J.A. et al., 2024. Identification of the first gestational ground for tiger sharks (Galeocerdo cuvier) in the Central Indian Ocean using a high-definition submersible ultrasound. Frontiers in Marine Science.

Further reading on Ocean Calling: More from the Journal · Ocean Atlas