Weekly Elephant Seal Monitoring Update: March 6, 2026

News This Week

• Biologists completed the last count of the elephant seal breeding season at Point Reyes National Seashore on March 2. Forty-eight cows and 45 nursing pups remain and we're up to 988 weaned pups on park beaches.
• We are still tagging weaned pups. We have currently tagged around 250 individuals.
• As of March 6, the Ken Patrick Visitor Center is dominated by 59 weanlings! Only two cows and two pups remain. V4 is still the alpha male!

Weanlings are curious and will often bite things in their surroundings: rocks, debris, and even their flippers. NPS / PRNSA / Aiko Goldston - NMFS Permit No. 27424

Weanlings have begun swimming in shallow water, such as this tide pool near Gus' Cove. NPS / PRNSA / Aiko Goldston - NMFS Permit No. 27424

A weanling pod at Gus' Cove. Most have molted into their new silver coats! NPS / PRNSA / Aiko Goldston - NMFS Permit No. 27424

Biologists will finish tagging weanlings next week. NPS / PRNSA / Aiko Goldston - NMFS Permit No. 27424

Elephant seal supermoms

Most elephant seal moms have weaned their pups, mated, and left Point Reyes beaches to find their first meal in over a month. But which ones will be back to give birth to another pup next winter, and the winter after that? Lifetime reproductive success (LRS) is a measure of an organism’s total genetic contributions to the next generation. It also offers clues about the pressures populations face, or how natural selection is working on them over time.

Researchers studied the LRS of female elephant seals at Año Nuevo State Park. They used data collected from 7,735 female elephant seals from 1963 to 2005 at Año Nuevo and beyond, including some flipper tag data from Point Reyes. They found that lifetime female reproductive success varies greatly due to three factors:

• High mortality prior to breeding. Surviving at sea is the first and greatest barrier to reproducing. Three out of four female weanlings in the study didn’t survive to the minimum breeding age of three. Young seals are vulnerable to predators like white sharks. And without experience to guide them, they may have trouble finding and catching enough food.
• Low reproductive success of young females. Among the females that survive to breed, three to six year-old females are the most numerous. But surprisingly, this group doesn’t have the most pups. Most young females only breed one to four times before they die. Recovery from their first reproduction seems to be difficult, partly because females aren’t fully grown until they’re six or seven. The youngest breeding females have lower lifespans and wean fewer healthy, fat pups. In other words, early breeding lowers these young females’ genetic contributions to the next generation.
• Exceptional reproductive success of long-lived females. Females that give birth to 10 or more pups in their lifetime, called “supermoms,” were responsible for more than half of the total pups of all females in this study.

Only six percent of females in this study reached supermom status. But this group contributed heavily to future generations. Most led long lives, bred every year, and successfully weaned healthy pups—a reflection of their size and foraging success—even on their earliest tries.

Two elephant seal cows bellowing at Gus' Cove. NPS / PRNSA / Aiko Goldston - NMFS Permit No. 27424

Preliminary Data

Total Elephant Seal Counts, Winter 2025-2026

Total elephant seal counts this season compared to average totals from 2021-2025 at the three Point Reyes National Seashore breeding colonies. This year's total count is similar to the five-year average. The Drakes Beach colony has numbers below the five-year average. The Point Reyes Headlands colony has numbers above the five-year average.

Female Elephant Seal Counts, Winter 2025-2026

Female elephant seal counts this season compared to average female counts from 2021-2025 at the three Point Reyes National Seashore breeding colonies. The total number of cows on Point Reyes beaches is above the five-year average. The Drakes Beach colony has numbers above the five-year average. The Point Reyes Headlands has numbers similar to the five-year average.

Elephant Seal Pup Counts, Winter 2025-2026

Number of elephant seal nursing pups counted at the three breeding colonies in Point Reyes National Seashore compared to the average number of pups surveyed at those colonies between 2021-2025. This year's pup count is above the five-year average.

Weaned Elephant Seal Pup Counts, Winter 2025-2026

Number of elephant seal weaned pups counted at the three breeding colonies in Point Reyes this winter compared to the average number of weaned pups surveyed at those colonies between 2021-2025. This year's weaned pup counts are below the five-year average.

Weekly Updates Recap

News this week

• Due to storms, biologists did not observe the first pup of the season for the Seashore overall. The first pup at the Ken Patrick Visitor Center (KPVC) was spotted on 12/28/25.
• Early January storms and king tides pushed many elephant seals to the beach in front of KPVC and Gus’ Cove at Chimney Rock.
• This week, a yearling with a fresh shark bite on it’s face showed up at KPVC. Biologists have observed several other seals in the Seashore with fresh shark bites.

What seal am I seeing?

Male elephant seals are distinctive with their proboscis. However, without a proboscis, it can be difficult to distinguish between the female and younger seals. Here is a description:

• Cows arriving between December and February are pregnant. Look for a slender snout and rotund midsection. Pregnant cows associate with Bulls and other pregnant cows. Pelt colors vary from pale to dark.
• Yearlings are the smallest seal aside from pups and weanlings. They often have patchy, pale, tan pelts. They are often seen on the periphery of a harem. They are on the beaches in small numbers during this time.
• Immature seals (both male and female) are longer in length than a yearling and can look like a cow, without the roundness of pregnancy. There aren’t many on the beaches during the breeding season. They are often seen on the periphery or by themselves.

Dye marking

Biologists are applying dye marks to alpha male elephant seals in the Seashore. Black hair dye is used for the dye and comes off with the pelt when the elephant seals molt later in the year. Dye marking helps to keep track of the alpha males' movements throughout the season. While some may stay with one harem for most of the season, others move to different harems. Look out for these dye marked bulls!

News This Week

• Elephant seals continue to arrive at Drakes Beach in front of the Ken Patrick Visitor Center! As of 1/16, there are 51 cows and 32 pups. Look out for the dye-marked bulls: V4, V5, and V6.
• Biologists have observed a higher number of seals with shark bite wounds this season.
• Elephant seal counts continue to increase across all sites. As of 1/15, we counted 1,288 total seals. We expect the peak count of the season to occur around the last week of January.

Elephant seal abundance in 2023

The National Marine Fisheries Service conducted aerial photographic surveys of northern elephant seals throughout California in 2023. They collected imagery in January, during the peak of the elephant seal birthing season. They've done similar surveys since 1990 to monitor abundance, distribution, and trends. With correction factors applied (e.g., to account for not all females arriving and giving birth at the same time), they estimated:

• Adult females: 45,536
• Births: 44,397
• Total 2023 northern elephant seal population: 194,903

The previous total population estimate in 2013 was 187,387 individuals. In 10 years, the population increased four percent, with an average annual growth rate of 0.39 percent.

81% of seals counted were observed on the Channel Islands!

Flipper tags

Small plastic tags are applied to the interdigital webbing of the rear flippers of weaned elephant seal pups. Each tag has a unique alphanumeric code and a color specific to each site. These flipper tags allow biologists at different sites to keep track of the elephant seals’ movement and gain more insight on pup mortality, life expectancy, site fidelity, and reproductive success.

Tag colors are site specific:

• **Pink **– Point Reyes and Farallon Islands
• **Green **– Año Nuevo
• **White **– San Simeon/ Piedras Blancas
• **Blue **– King Range in the Lost Coast area, Vandenberg Space Force Base, and Mexico

Here are some recent tags observed in the Seashore.

News this Week

• The pups are weaning! The first pup at the Ken Patrick Visitor Center weaned this week. Mating behavior is ramping up as more pups wean and cows enter estrus.
• The yearling with a shark bite on it’s face left the beach in front of the visitor center on Sunday and headed out to the sea.

Elephant seal numbers increase day by day. Around 300 more pups were born in the Seashore since the last weekly update.

Attempted predation on weanlings

Members of our monitoring team published an observation about attempted predation on elephant seal weanlings at South Beach in Aquatic Mammals last year.

In 2020, while conducting breeding season surveys, biologists noticed at least 34 weanlings with hind flipper injuries. The injuries ranged from small segments to nearly half of the hind flipper. The elephant seals were alive and healthy when this happened. We placed wildlife cameras at the colony and photos captured footage of a coyote repeatedly biting the hind flippers of a weanling. Prior to this, there were just two documented reports of coyotes preying on abandoned or weakened pups in the Seashore. This is the first observed incident of attempted predation by coyotes on apparently healthy elephant seals. We don't know how the flipper injuries affected the seals’ fitness.

We haven't seen similar injuries to healthy elephant seal weanlings in subsequent years.

See the article below for more photos. There's also a video.

Ballinger, K. A., Cox, M. A., Horowski, D. N., & Codde, S. A. (2025). Attempted predation on northern elephant Seal weanlings (Mirounga angustirostris) by coyote (Canis latrans) in Point Reyes National Seashore, California. Aquatic Mammals, 51(4), 363-370.

News This Week

There is an elephant seal mother and pup at the Point Reyes Lifeboat Station! The pup appears to be two weeks old. Biologists presume the pair were brought over with the king tides.

The peak of the elephant seal breeding season has passed. Total seal numbers are dropping as more cows wean their pup and leave.

Milk thieves!

During their 8-12 week post-weaning fast, weaned pups are left alone on Point Reyes beaches. They learn how to swim and continue their physical development in preparation for their first foraging journey out to sea. They also lose weight.

In a study at Año Nuevo State Park, CA, researchers estimated that weaned pups lose approximately 1.3 to 2 pounds per day. By the time they leave the beach, they’ll lose about 25 percent of their body weight.

On average, pups are about 300 pounds when they are first weaned. But some weaned pups will steal additional milk and grow even larger. A few grow to be super weaners nearing 600 pounds! In another study of weaned pups at Año Nuevo, researchers found that super weaners tend to be male. Males pups were more successful at stealing milk. They’d steal more often, more persistently, and for longer than females. Several observations were made of a male attempting to steal milk from as many as 5-10 females in succession! Although this strategy almost always involved a bite from one or more females, some male weaners pursued milk-stealing daily for as long as 3.5 weeks. It was rare for a female weaner to steal milk for more than a single day.

Flipper tag updates

Some experienced seal moms are here! We observed one 15-year-old, three 13-year-olds, two 12-year-olds, and two 11-year-olds last week. Above is a 13-year-old cow at the Elephant Seal Overlook. Older females wean larger pups on average, due to their ability to select an optimal location on the beach for nursing. They also produce milk with a high fat content earlier in the lactation period.

A tagged female ‘V73’ was observed with a pup at KPVC this week. She was one of the numerous cows that arrived at KPVC in 2019 (the first year we had a large group of females pupping at KPVC). She was flipper tagged as a cow in 2019, so her age is unknown. She pupped further down on Drakes Beach in 2020 and 2022. In 2024, she returned to pup at KPVC. Hope to see you next year!

News This Week

• There is an elephant seal mother and pup at the Point Reyes Lifeboat Station! The pup appears to be two weeks old. Biologists presume the pair were brought over with the king tides.
• The peak of the elephant seal breeding season has passed. Total seal numbers are dropping as more cows wean their pup and leave.

Milk thieves!

During their eight to 12 week post-weaning fast, weaned pups are left alone on Point Reyes beaches. They learn how to swim and continue their physical development in preparation for their first foraging journey out to sea. They also lose weight.

In a study at Año Nuevo State Park, CA, researchers estimated that weaned pups lose approximately 1.3 to two pounds per day. By the time they leave the beach, they’ll lose about 25 percent of their body weight.

On average, pups are about 300 pounds when they are first weaned. But some weaned pups will steal additional milk and grow even larger. A few grow to be super weaners nearing 600 pounds! In another study of weaned pups at Año Nuevo, researchers found that super weaners tend to be male. Males pups were more successful at stealing milk. They’d steal more often, more persistently, and for longer than females. Several observations were made of a male attempting to steal milk from as many as five to 10 females in succession! Although this strategy almost always involved a bite from one or more females, some male weaners pursued milk-stealing daily for as long as 3.5 weeks. It was rare for a female weaner to steal milk for more than a single day.

Flipper tag updates

Some experienced seal moms are here! We observed one 15-year-old, three 13-year-olds, two 12-year-olds, and two 11-year-olds last week. This is a 13-year-old cow at the Elephant Seal Overlook. Older females wean larger pups on average, due to their ability to select an optimal location on the beach for nursing. They also produce milk with a high fat content earlier in the lactation period.

A tagged female ‘V73’ was observed with a pup at KPVC this week. She was one of the numerous cows that arrived at KPVC in 2019 (the first year we had a large group of females pupping at KPVC). She was flipper tagged as a cow in 2019, so her age is unknown. She pupped further down on Drakes Beach in 2020 and 2022. In 2024, she returned to pup at KPVC. Hope to see you next year!

News this week

• It is currently around the peak of elephant seal mating time at Point Reyes National Seashore!
• The last of the pregnant females have likely given birth. Biologists observed a couple newborn pups this week.
• Pups are weaning every day. 287 pups have weaned since last week.

To eat or to rest?

When diving, elephant seals must balance foraging, resting, and avoiding predation. They also must account for lessening daylight, shifting buoyancy as they gain fat, and the daily vertical movements of their prey in the water column—down during the day, and back up at night. At night, elephant seals face a trade-off: they can forage more efficiently, or they can rest via drift dives in the safety of darkness, when predators can’t see them as well.Researchers at UC Santa Cruz collected data on 71 elephant seals during their foraging migration. They wanted to determine how the seals adjust their use of the day and night based on their nutritional state and the duration of daylight.

Their findings showed that elephant seals mainly time their rest based on predation risk after sunrise, rather than circadian rhythm or foraging time. Early in migration, when the seals are building up fat, they go on high-efficiency foraging dives at night. Then they rest just after sunrise. As they gain fat throughout migration, their buoyancy shifts from negative (seals sink while drifting) to positive (seals float while drifting). Once seals switched to positive buoyancy, they shifted their drift dives to before sunrise, in darkness. Over the course of migration, the proportion of daytime rest decreased from 80 to 30 percent. The researchers also found that seals account for their changing buoyancy by starting their drift dives at greater depths to avoid drifting in shallower water, where there is more light and higher predation risk.

As daylight decreased throughout migration, seals also spent more time resting at night. But their foraging time remained mostly unchanged. Once in better body condition, seals are more motivated to prioritize resting in safer nighttime conditions.

Reference: Beltran, R. S., et al. 2021. Lightscapes of fear: How mesopredators balance starvation and predation in the open ocean. Science Advances, 7, eabd9818. DOI:10.1126/sciadv.abd9818

Flipper tagging begins

Biologists have started applying flipper tags to the weaned pups. How is this done? Biologists quietly approach sleeping weaned pups from behind. If the underside of the weaned pup is exposed, they will determine the sex. Then, they softly pick up a hind flipper and use a tagging instrument to apply a flipper tag into the interdigital webbing of the hind flipper.

News this Week

• Elephant seal numbers are dropping as cows depart Point Reyes. As of February 18, 361 total cows and 325 total pups remain at the Seashore.
• As of February 20, there are 54 weanlings at the Ken Patrick Visitor Center! There are a total of 676 weanlings at the Seashore.
• The storm over the weekend brought many subadult males up into the ice plant at the visitor center.

Weanling development

During the eight to 12 weeks of the post-weaning fast, weanlings are undergoing physiological changes to prepare them for their first foraging migration. The factors below go hand in hand to prepare the weanlings for continuous, deep dives!

Increasing oxygen storage capacity

Blood is the most important oxygen storage site in phocid (earless) seals. It contains approximately 65% of their total oxygen stores. Blood oxygen storage capacity is determined by hemoglobin concentration and blood volume. As weanlings lose weight during their fast, their hemoglobin and blood volume increases. Consequently, their oxygen stores increase by about 46.7 percent over the fast.

Increasing ability to decrease metabolic rate

Metabolic rate decreases with age and with time spent fasting. Weanlings’ oxygen consumption grows more consistent throughout their post-weaning fast. That suggests that they gain more control over their metabolic rate as their oxygen stores and diving experience increases. Their metabolic rate decreases by 50 percent over the course of their fast.

Changing diving behavior

During the post weaning fast, the weanlings go from spending less than two percent to 52% per day in the water, with most time being concentrated at night. Their duration of shallow dives increases from two minutes to six minutes. The increased duration of dives and the total amount of time spent diving also helps to decrease their metabolic rate.

Reference: Thorson, P.H., and Le Boeuf, B. J. 1994. Developmental aspects of diving in northern elephant seal pups. In Elephant seals: population ecology, behavior, and physiology. Edited by B. J. Le Boeuf and R.M. Laws. University of California Press, Berkeley. pp. 271 -289.

Shark bites

We have seen more elephant seals with fresh shark bites than usual this season. The seals’ main predators are orcas and white sharks. The shark-bitten seals seen at Point Reyes are likely from white sharks, which are present in Drakes Bay. We also see many healthy elephant seals with healed wounds every year, meaning not all shark bites are fatal. Elephant seals have robust healing capabilities. In addition, the shark bites often don’t reach beyond the seals’ thick blubber layer, which protects their internal organs. The pictures below show different shark bite wounds seen at Point Reyes throughout the years.

• Healed shark bitten female
• Female with a fresher shark bite
• Flipper bite
• Injured subadult male

News this Week

• Adult female elephant seal numbers have dropped rapidly at Point Reyes National Seashore. Less than 100 cows and nursing pups remaining in the Seashore.
• The oldest weanlings are around two months old. Many weanlings are now practicing their swimming skills in the breaking tides.
• Biologists are applying flipper tags to weanlings. About 200 seals have been tagged.

Elephant seals as sentinels of the open ocean: Fish abundance

Open ocean ecosystems are hard to study. That includes the mesopelagic zone—also called the twilight zone—several hundred to a few thousand feet below the surface. But elephant seals are top marine predators that travel long distances. They also dive to great depths, and primarily forage in this zone. As a result, they can serve as sentinels of the open ocean, helping us to better understand what’s happening there.We know some of what’s happening from measuring ocean surface conditions like air pressure, water temperature, and circulation. But what do changes in these conditions mean for ocean life? By correlating elephant seal population trends with different ocean conditions, researchers at the University of California Santa Cruz found some answers.

The researchers examined long-term elephant seal monitoring data collected between 1982 and 2015. They found relationships between ocean conditions and elephant seal survival, population growth, and reproductive success. For example, cooler water and more circulation in the eastern Pacific was good for the seals. Such conditions correlated with seals gaining more weight and more pups surviving their first year. The researchers quantified the relationships and were able to predict fish abundance in the twilight zone.

Researchers then used mathematical models to estimate how twilight zone fish abundance would affect the elephant seal population under different ocean conditions. In their simulation, they used historical first-year survival rates to project the population 20 years into the future. The historical survival rates diverged sharply. In 1987, for example, favorable ocean conditions led to 61 percent first-year survival. In 1997, ocean conditions were poor and first year survival was only 18 percent. The simulation showed that just one favorable year could lead to huge differences in population growth. In a favorable year, they estimated that 24,588 more elephant seals would survive their first year. After 20 years, that would translate to 312,812 additional seals in the population.

This study highlights elephant seals’ sensitivity to fluctuating ocean conditions and shows their importance as sentinels of prey populations and ocean ecosystem health. It may also provide a baseline for assessing changes to life in the twilight zone into the future.

Elephant seals as sentinels of the open ocean: Pollutants

Persistent organic pollutants (POPs) are toxic compounds resistant to biological and chemical degradation. They can enter food webs and pass from one species to the next. They accumulate in predators higher up the food chain, and persistent exposure to POPs can lead to adverse health effects. Marine mammals accumulate most of their POPs from food. And elephant seals are long-lived predators that forage in the twilight zone. Thus, they are good sentinels of POP contamination in remote ocean habitats.

Researchers studied the accumulation of several different POPs in elephant seals. They sampled the blubber and blood of elephant seals at the start and end of their seven-month foraging trip. In their analyses, they looked for differences between males and females. They expected females to have lower concentrations, because they pass much of their POP burdens on to their pups during pregnancy and lactation.

The now-banned pesticide DDT was the predominant POP found in elephant seals' blubber and blood. Males had greater concentrations of POP compounds than females, as expected. Though, foraging behavior in males and females also likely contributed the differences. Males and females forage (and accumulate POPs) in different parts of the ocean. Males forage in the coastal regions while females forage more offshore. Seals that foraged further south and closer to the continental shelf had the highest concentrations of POPs. However, regardless of any differences in behavior and pregnancy, all seals gained POPs while foraging.

The POP load on elephant seals shows that exposure isn't the same across the ocean. Different foraging behaviors can exacerbate or mitigate exposure. It also shows that the deep ocean may serve as a sink for POPs, where they can enter and reenter marine food webs. Even remote areas far from where and when POPs likely entered the environment may be sources of exposure.

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