Last updated: January 19, 2023
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Elephant Seal Monitoring Season Summary: Winter 2021-2022
Season Highlights
- The breeding elephant seal population has increased this year, continuing the growth trend at the Point Reyes rookery.
- A tsunami and two king tide events during pupping did not have a major impact on pup survival to weaning. The highest count of weaned pups was 1126 out of 1294 pups born.
- Park researchers flipper tagged over 500 weaned pups.
Left image
Point Reyes Headlands elephant seal colony early in the breeding season
Credit: NPS / Marjorie Cox, NMFS Permit No. 21425
Right image
Point Reyes Headlands colony at the peak of the breeding season
Credit: NPS / Marjorie Cox, NMFS Permit No. 21425
NPS / Marjorie Cox - NMFS Permit No. 21425
Drakes Beach Expansion
As elephant seal numbers increase at the Point Reyes colony, movement between subsites has been observed within the park. One of the most dramatic changes has been observed on Drakes Beach. Researchers divide the long stretch of Drakes Beach into two sub-sites: DB1 is the beach directly underneath the Elephant Seal Overlook and DB2 is the much longer stretch of beach from the end of DB1 to the Kenneth Patrick Visitor Center. Overall numbers on Drakes Beach are increasing, most dramatically on DB2, with over 500 breeding females observed at the peak of the 2022 season! DB1 numbers are declining, which is likely attributing to the growth at DB2.
Drakes Beach Peak Breeding Female Elephant Seals
Sensational Seal Sighting!
Most breeding seals have left Point Reyes beaches, but that doesn’t mean that park visitors have missed out on amazing elephant seal viewing opportunities! Weaned pups will remain on beaches through April and a few sub-adult and adult males will remain into late March. Seals can be viewed from The Elephant Seal Overlook and at the beach in front of the Kenneth Patrick Visitor Center. In 2021 and 2019, due to winter storm events, seals gave birth directly in front of the visitor center. This season, pregnant females were deterred from giving birth in front of the visitor center, so no harem was established. However, weaned pups have still moved into the area. Elephant seals are present at Point Reyes year-round. Adult females and juveniles return to molt in March-June, adult males molt in June-August, and young seals return in the fall for the juvenile haul out. Remember to keep your distance for your safety and to avoid disturbance to resting seals.
NPS / Carlo Arreglo - NMFS Permit No. 21425
NPS / Marjorie Cox, NMFS Permit No. 21425
Tag Team!
Point Reyes researchers have been busy flipper tagging weaned pups throughout the park. The seals are tagged in order to track their movement within the park and to other colonies. When the tag is re-sighted it provides a movement history for the seal. If the tag is applied at weaning, then researchers will also know the seal's age, as long as it keeps the tag. The tags are very lightweight and are applied in the inter-digital webbing of the hind flipper. Different colonies have different colors of tags: Point Reyes and the Farallon Islands are pink, Ano Nuevo is green, and San Simeon is white.
NPS / Marjorie Cox, NMFS Permit No. 21425
NPS / Marjorie Cox, NMFS Permit No. 21425
By the Numbers
Elephant Seal Breeding Season Peaks, 2017-2022 (from direct ground counts)
Total Elephant Seal Counts, Winter 2021-2022
Female Elephant Seal Counts, Winter 2021-2022
Elephant Seal Pup Counts, Winter 2021-2022
Weaned Elephant Seal Pup Counts, Winter 2021-2022
Weaned Elephant Seal Counts, Winter 2021-2022
Weekly Updates Recap
Northern Elephant Seal 101
Adult Male Weight: 4400-6000 lbs.
Adult Female Weight: approx.1300 lbs.
Pup Weight: 60-75 lbs.
Weaned Pup Weight: approx. 300 lbs.
Adult Male Length: 12-18 ft.
Adult Female Length: 9-10 ft.
Pup Length: 3.2-4 ft
Nursing Duration: approx. 28 days
Male Lifespan: 12-14 years
Female Lifespan: 16-18 years
Yearly Migration Distance (Male): 13,000 miles
Yearly Migration Distance (Female): 12,000 miles
Dive Depth: avg. 1,000 ft.
Deepest Recorded Dive: 5,788 ft. (adult female)
Perfect Timing
Female elephant seals spend most of the year foraging in the open ocean, often over 1,000 miles from land. The seals give birth at roughly the same time every year, which means timing is very important in order to arrive on land just before giving birth. If the seals leave too soon, they miss out on foraging opportunities, and if too late they could lose their pup at sea. A recent study out of UC Santa Cruz involved satellite tracking female seals to determine the interval from when seals arrive on land to when they gave birth. The results show that on average female seals gave birth 5.5 days after arrival. This small margin of error demonstrates that the seals know when birth is imminent. The study also found that in the two weeks before birth, seals began to spend less time foraging and more time transiting. Female seals that were farther away from the colony traveled at a higher rate of speed. Baby on board!
News This Week
- Female elephant seal arrivals and pup births are ramping up.
- Drakes Beach in front and to the left of the parking lot is open but may close dependent on seal presence.
- The Fish Dock, the beach at the Historic Lifeboat Station, the beach to the right of Drakes Beach parking lot, and the southern end of South Beach are closed.
Make Way For Mamas!
After approximately seven months foraging in the open ocean, female seals have increasingly been showing up on Point Reyes beaches to give birth. Northern elephant seals have a high rate of natal fidelity, which means they often return annually to the same colony and even the exact beach where they were born. However, researchers do see breeding age seals in Point Reyes that were born at other colonies, like Año Nuevo (identified through flipper tags). It is also common to see movement within the Point Reyes colony. This past week park staff resighted a pregnant female on Drakes Beach who was tagged as a pup at the Historic Lifeboat Station and gave birth there in 2021. It seems she was ready for a change of scenery!
Swim Speed
Technology has done amazing things for elephant seal research, which has helped to increase knowledge of their behavior at sea. For example, we now know that, when at sea, elephant seals spend about 90% of their time underwater, surfacing for only about two minutes between dives. Their average dive speed is about six miles per hour (mph), and can accelerate up to 13 mph. During certain dives, the swim velocity slows considerably, and researchers believe that seals are resting during these “drift” dives. In comparison, a California sea lion can swim up to 25 mph and a great white shark up to 30 mph!
News This Week
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Female elephant seal arrivals and pup births have greatly increased.
- Drakes Beach in front and to the left of the parking lot is open but may close dependent on seal presence.
- The Fish Dock, the beach at the Historic Lifeboat Station, the beach to the right of Drakes Beach parking lot, and the southern end of South Beach are closed.
Tsunami!
Last weekend’s tsunami triggered beach closures park-wide to protect human visitors. The elephant seal colony had no choice but to stay put, hunker down, and get wet. Beaches with high seal presence were repeatedly inundated by tidal surges that corresponded with the morning high tide. While there is evidence of some pup loss after this event, researchers did not see a dramatic drop in pup numbers. Elephant seal pups are not able to swim, if they get swept out, and they may drown or be permanently separated from their mom. Experienced moms know to block their pups from the water’s edge using their large body to prevent the pup from being lost to the sea, just one of the behaviors seal mamas exhibit when it comes to ferociously protecting their pups!
Them’s Fighting….Roars? Burps? Claps!
The vocalizations of male northern elephant seals, also called ‘clap threats’, are often heard at colonies. Recent research out of UC Santa Cruz emphasizes the importance of these vocalizations in determining if males will engage in physical altercations. Clap threats of individual males have an acoustic signature, distinct for each individual. While alpha males will defend their harem against all subordinate male intruders, lower ranking males use these vocalizations to determine if a fight is worth the energy expenditure. The seals can recognize clap threats from individuals they have encountered before, remembering the vocal signature of other seals even from previous years. If the vocalization they recognize is from a seal that dominated them in the past, the seal will avoid a fight they are likely to lose.
Dominant D3
Park visitors should keep an eye out for a dye marked bull visible from the Elephant Seal Overlook. The bull, dye-marked “D3” on his posterior, left, and right side, is also flipper tagged. D3 was tagged as a pup on Drakes Beach in 2011. This 11-year-old bull is currently enjoying alpha status and was also resighted as an alpha bull in 2020 and 2021! This is quite an achievement, as only about 5% of males born survive to adulthood and about 1% of males born successfully mate.
News This Week
- A record high number of female elephant seals are present.
- Weaned pups and mating activity have been observed.
- Drakes Beach in front and to the left of the parking lot is open but may close dependent on seal presence.
- The Fish Dock, the beach at the Historic Lifeboat Station, the beach to the right of Drakes Beach parking lot, and the southern end of South Beach are closed.
Squawk N Roll!
It is getting very noisy at Point Reyes! Elephant seals have a variety of vocalizations, and the careful listener can distinguish who’s who by the wide array of sounds they make. Elephant seal pups use a loud chicken-like squawk to get their mother’s attention when they are hungry or distressed. Female elephant seals have a warbling call when communicating with their pup. A recent study out of UC Santa Cruz found that female seals can recognize the specific vocalizations of their own pup, however, individual females vary in their consistency in this recognition. Beware a protective mama seal! The sweet warbles of the females can easily change to throaty roars if other seals, birds, or people get too close to their pups.
May the Lurk Be With You
For male seals, the opportunity to mate in an elephant seal colony is hard to achieve, and typically only the largest and most dominant males are successful. This doesn’t mean that younger seals won't make numerous mating attempts. Subordinate males will lurk on the periphery of a harem, and sneak in when the alpha bull is unaware. However, these mating attempts are rarely successful, as female seals are usually not receptive to the non-alpha. Female seals will loudly protest the attentions of the interloper and alert the alpha. Often all it takes is a raised head and a little side eye from the alpha to chase the smaller male out of the harem.
News This Week
- A peak count of 1,371 breeding female elephant seals was recorded on January 24th. This week female numbers began to decline.
- First molted weaned pup of the season was spotted.
- King tides over seven feet did not appear to cause major disturbance or pup loss to colony.
Fish Surprise!
Elephant seals are known for their VERY deep-water foraging behavior, with females primarily foraging in the pelagic zone off the continental shelf and males benthically foraging near the shelf slope. So, park researchers were very surprised to see a juvenile seal exiting the water with a spotted ratfish in its mouth! The seal was observed carrying the fish out of the water, and when researchers returned a few minutes later the seal was still there but the fish appeared to have been consumed. After consulting with other researchers in California this seems to be an extremely rare observation. Juvenile seal foraging behavior is not as deeply researched as adult foraging. It is possible this observation was an anomaly, or these young seals may forage closer to shore. With new technologies, this research topic is being explored and it will be exciting to see what the results show.
Seal-ebrity News
Two seal elders of Point Reyes were spotted this week: D3 and “Shark Lady”. Bull D3 is still holding down alpha status on Drakes Beach. This eleven-year-old male can be seen in the first harem under the Elephant Seal Overlook. Keep an eye out for his dye mark (D3). Park researchers were thrilled to see a pregnant female seal affectionately called “Shark Lady”. This female, also visible from the overlook, has a massive, healed shark wound in her mid-section. Shark Lady was tagged as a pup at Año Nuevo in 2005. She is 17 years old and has been spotted in Point Reyes since 2013, either pregnant or with a pup! It is incredible that she has been so successful after surviving such a catastrophic injury.
News This Week
- Female elephant seal departures begin to ramp up, with very few new arrivals of pregnant females.
- Unseasonably warm temperatures effect seal behavior, such as prompting moms and pups to move down to the water.
- Biologists have begun tagging weaned pups.
It’s Hot Out Here For A Seal
An unseasonably warm and sunny week in Point Reyes showcased the elephant seals’ strategies to beat the heat. Accustomed to spending most of their life in very cold water (average of 39 degrees Fahrenheit at the meso/bathypelagic boundary) seals must cool their bodies while on land. In warm temperatures, blood flow is increased to the extremities, where seals can “dump” heat. Seals will raise their flippers into the air to encourage this process, the air flow over the flipper cools the blood before it returns to the core of the body. Another common sight at elephant seal colonies is sand-flipping. Seals will flip wet sand onto their bodies, and through evaporation their body temperature is lowered. Sand flipping behavior is observed even in very small pups! These warm days also encourage a special phenomenon seen in the calm near-shore waters of Drakes Bay—females taking their pups into the water so both can cool off. Typically, females avoid the water’s edge when they have a pup since elephant seal pups are not good swimmers. But in the protected bay, seal moms are able to enjoy the chilly water while keeping their pups safe.
Pup Papas
Elephant seals are an example of extremes, from their massive size to their incredible dives. Another example of these extremes is the high variance of male mating success. Dominant alphas try to prevent females from mating with any subordinate males in order to sire as many pups as possible. Research shows that the reproductive success of alphas varies considerably from colony to colony, from harem to harem, and even between southern and northern species. Southern elephant seal alpha males have been shown to have a higher rate of reproductive success. One reason why northern alphas may be less successful is that the genetic bottleneck, caused by their near extinction, may have negatively affected their sperm quality. It is also difficult for researchers to determine paternity in northern seals due to reduced genetic variation, also attributed to their near extinction.
News This Week
- Colony numbers decline, as female elephant seals continue to leave in large numbers.
- The peak of mating began, with many observations of mating activity.
- Subordinate males surround the harems in an attempt to mate with departing females.
No Wet Whistles
The incredible feat of prolonged terrestrial fasting (about 3 months for males, 1 month for females, and 2-3 months for weaned pups) doesn’t just mean the seals aren’t eating but also that they are not taking in water. Seals do not drink water. Instead, they acquire water from their prey and from metabolic water production. This poses a problem when seals are not consuming prey while on land. Elephant seals, though, have developed some incredible physiological adaptations for water conservation. During the fast, seals reduce their excretions, and because seals don’t have sweat glands, they have no cutaneous water loss. Respiratory evaporative water loss (REWL) must be reduced during the fast and the seals have incredibly complex boney structures in their nasal cavity called turbinates. The turbinates, covered in soft tissue, allow the moisture from exhaled air to condense inside the nasal cavity, thus keeping the water inside the seal’s body. Another way that seals reduce REWL is through apneustic breathing, a period of extended breath holds interspersed with periods of rapid breathing. Research has found that efficiency of water conservation correlates with longer durations of apnea. These breath holds allow for fewer lung-fulls of humidified air to be expelled from the body. Don’t hold your breath waiting for a sleeping adult seal to take a breath, you could be waiting over 20 minutes!
The Incredible Shrinking Seals
Elephant seals are renowned for their massive size, but a visit to the colony late in the breeding season displays the incredible toll of prolonged fasting on body size - the seals are shrinking by the day! When the largest bulls arrive, they can way up to 5000 lbs., but by the end of the season they may lose up to 40% (2000 lbs.) of their weight. Not only are male seals not eating, but they are incredibly active; moving around the colony, fighting, and mating (or at least trying to). While female seals are much smaller, they are no small potatoes, weighing an average of 1500 lbs. Females are more sedentary, but they are nursing their pups on incredibly calorie rich milk and can lose about 36% of their body weight (500 lbs.).
News This Week
- Less than 200 nursing female elephant seals remain in the colony, down from a peak count of 1,370.
- Weaned pup pods are beginning to form at all sites, and there are over 1,000 weaned pups in the park.
- Tagging efforts of weaned pups continue.
Plump Pup Paradise!
It is a magical time at Point Reyes, when groups of weaned pups gather by the dozens and form weanling pods! Elephant seal pups receive no maternal care after weaning, so at about 4 weeks old they are on their own. These pups do not depart for sea until they have spent some time on the beach and in near shore waters where they begin to develop their diving ability and swimming skills. During this time, called the post-weaning fast, the seals also began to exhibit social behaviors that mimic the aggression they will display as adults. Male weanlings will mock fight and can be seen giving neck bites, neck presses, and body slams; a much more adorable version of the intense physical altercations they will get into as adults. The post weaning fast will last 2-3 months, after which the pups will be proficient divers and swimmers. In a recent study out of UC Santa Cruz, a weaned pup was recorded diving 90 ft on her first dive after leaving the breeding colony, and after 3 days at sea she was diving well over 700 feet!
EGGcelent Timing
When female seals depart the colony, they have likely mated multiple times, and are leaving the beach with a fertilized egg in their uterus. Pinnipeds (seals and sea lions) employ a reproductive strategy called delayed implantation, a process in which a fertilized egg floats in the uterus and does not start to develop immediately. This delay allows for the timing of the birth to correlate with favorable environmental conditions, regardless if mating occurs early or late in the breeding season. The total gestation period for northern elephant seals is approximately 11 months. After successful mating, female seals will delay implantation for about 3 ½ months during their post mating foraging trip and their return to land to molt. The embryo will implant in the uterus about 7 ½ months before birth. Examples of other animals that delay implantation are Ursids (bears) and Mustelids (weasels and otters). It is unknown what mechanism triggers the implantation, but it likely involves hormones such as progesterone.
News This Week
- Very few nursing female elephant seals remain on park beaches.
- Weaned pups have been observed venturing into the water.
- Tagging efforts of weaned pups continue.
Let’s Talk About…Stimulus Generalization
With very few adult females remaining at Point Reyes, the competition for mating opportunities is fierce, and typically only the oldest and largest males will succeed. Due to the lack of mating opportunities, it is not uncommon to observe male seals attempting to copulate with weaned pups. The males will display the same behaviors towards weaned pups, such as fore-flipper holds, neck presses, and neck biting, as they display when mounting adult females. Typically, these attempted copulations with pups are by sub-adult males. A combination of strong sexual drive, sexual inexperience, and limited access to estrus females stimulates males to generalize their sexual response. These encounters are typically short lived, and it is very rare for pups to be severely injured or killed during the mounting attempts. Weaned pups employ the same strategies as females during unwanted mating attempts, such as vigorously protesting and finding safety in large groups.
Paddling Pup Parade
The post weaning fast is in full swing for Point Reyes pups! Elephant seal pups live off their fat reserves (acquired from their mother’s rich milk) during the 2-3 months they spend at their birth site before leaving for the open ocean. After weaning, pups spend time resting on land and grouping up into weanling pods. Pups begin to venture into shallow areas, such as tide pools, and gradually venture out into deeper water where they learn to swim and dive. While not feeding during this time, the pups are practicing the skills they will need to become successful deep-sea foragers. Research has shown that pups weaned later in the season venture into the water sooner, as they observe the in-water behavior of older weaned pups. The best time to observe paddling pups is in the early morning or evening, as they are often resting on shore during mid-day.
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