{"id":664246,"date":"2026-05-25T15:00:13","date_gmt":"2026-05-25T15:00:13","guid":{"rendered":"https:\/\/www.newsbeep.com\/us\/664246\/"},"modified":"2026-05-25T15:00:13","modified_gmt":"2026-05-25T15:00:13","slug":"rare-animal-photographed-in-golden-gate-park-pond-total-shock","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us\/664246\/","title":{"rendered":"Rare animal photographed in Golden Gate Park pond: ‘Total shock’"},"content":{"rendered":"

As the fog burned off on a recent April afternoon, Richard Hasegawa made his way along the southern edge of Golden Gate Park<\/a>, passing the hustle and bustle of joggers and cyclists on MLK Drive before reaching a secluded spot near Mallard Lake. It took the biologist no more than five minutes of sifting through twigs and leaves at the water\u2019s edge before he turned over a piece of wood and knew he had found what he was searching for.<\/p>\n

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There, wriggling in the sunshine, were two creatures that had never been documented on\u00a0iNaturalist<\/a> before: the Golden Gate leech, a predatory worm that only exists in the freshwaters of San Francisco\u2019s largest park.<\/p>\n

\u201cI just felt this dopamine rush, this great feeling of \u2018eureka!\u2019\u201d said Hasegawa, who lives in Berkeley and works for the environmental consulting firm WRA. \u201cIt filled me with a sense of wonderment, that there are things we walk past every day like this without realizing.\u201d<\/p>\n

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\"Richard<\/p>\n

Richard Hasegawa captured the photos using an Olympus Tough TG-6 camera.<\/p>\n

Richard Hasegawa\"The<\/p>\n

The Golden Gate Leech was photographed on April 26, 2026.<\/p>\n

Richard Hasegawa<\/p>\n

But he couldn\u2019t dwell on these feelings for long. Hasegawa had other work to get to: namely, \u201cwrangling\u201d the leeches for their close-up. Wielding a small digital camera in one hand and a twig in the other, he gently nudged the pea-sized animals into a jerry-rigged setup with an aquarium box. After providing them with a bit of moisture so they wouldn\u2019t get dehydrated, he snapped away, capturing the distinctive black speckles on the underside of their abdomens and the dark ring on their posterior suckers. The muscular disc at the tail end of their bodies allows them to crawl, \u201cadvance on their prey and engulf it whole,\u201d Hasegawa said. \u201cUnfortunately, I didn\u2019t get to witness that, but it\u2019s incredible to see.”<\/p>\n

From there, he uploaded<\/a> the images to iNaturalist and waited. Dozens of replies piled up. A few days later, while he was out doing field work, he learned that his observation of the leech, made during this year\u2019s City Nature challenge<\/a>, was the first ever recorded on the app.\u00a0<\/p>\n

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\u201cI was in total shock,\u201d he said.\u00a0<\/p>\n

\"View<\/p>\n

View of Mallard Lake in Golden Gate Park in San Francisco.<\/p>\n

Screenshot via Google Street View<\/p>\n

Founded in 2008,\u00a0iNaturalist is now a joint initiative between the California Academy of Sciences and the National Geographic Society that allows users to upload and record photos of plants, animals and fungi for other users to help identify. Data from the public platform is used by scientists to track the population and range of various species over time.\u00a0<\/p>\n

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A decade ago, Cal Academy launched the City Nature Challenge<\/a> as a way to encourage people to document the biodiversity in their backyards by using the community science app. What began as a friendly competition between San Francisco and Los Angeles to log the most observations has since become the largest global census of its kind, with millions of observations to date.\u00a0<\/p>\n

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Screenshot of Golden Gate Leech at Mallard Lake in Golden Gate Park in San Francisco.<\/p>\n

Screenshot via YouTube\"Screenshot<\/p>\n

Screenshot of Golden Gate Leech.<\/p>\n

Screenshot via YouTube<\/p>\n

Rebecca Johnson, director of the Center for Biodiversity and Community Science at Cal Academy, told SFGATE that during this year\u2019s challenge, which took place from April 24-27, 106,350 people participated across 754 cities to make over three million observations. In the Bay Area, over 3,000 users recorded nearly 2,000 species, almost 200 of which were threatened or endangered, she said. The leech joins 70 new species documented on iNaturalist for the first time across the world.<\/p>\n

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\u201cThe distribution of plants and animals is critically important for us to know as folks who focus on conservation,\u201d Johnson said. \u201cScientists can\u2019t be everywhere, so these sightings help us better understand species distributions and how they\u2019re changing. It\u2019s the biggest and most complete picture that we have of biodiversity.\u201d\u00a0<\/p>\n

\"The<\/p>\n

The species is only found in the ponds of Golden Gate Park.\u00a0<\/p>\n

Richard Hasegawa\"Parents<\/p>\n

Parents carry their young to feed.<\/p>\n

Richard Hasegawa\"The<\/p>\n

The species was likely introduced to San Francisco in the 1850s.<\/p>\n

Richard Hasegawa<\/p>\n

Hasegawa told SFGATE he has been casually participating in the City Nature Challenge for the past few years, submitting photos and volunteering to help people learn more about the app. This year, he was encouraged to take part in a bioblitz<\/a> to find the coastal green\u00a0hairstreak, a rare butterfly that was thought to be extinct in San Francisco but was rediscovered in the early 2000s<\/a>, prompting habitat restoration efforts.<\/p>\n

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Before setting out, Hasegawa decided to see if there were any other unique and overlooked species in the area that he could find. From there, he discovered a paper from the German evolutionary biologist Dr. Ulrich Kutschera, who was the first to describe and identify the Golden Gate leech in what is now Great Blue Heron Lake in 1987. Delving deeper, Hasegawa learned that by 2007, changing conditions in the popular duck pond likely ousted the \u201csmall brooding\u201d animals, but that they could still be found in cleaner nearby ponds, including some in the Botanical Gardens and Mallard Lake.\u00a0<\/p>\n

\u201cI thought this would be a convenient way to go look for them,\u201d Hasegawa said.\u00a0\u00a0<\/p>\n

\"Scientist<\/p>\n

Scientist Ulrich Kutschera displays his book, *Das Gender-Paradoxon* (The Gender Paradox), in the courtroom. July 5, 2019.<\/p>\n

picture alliance\/Getty Image<\/p>\n

Experts believe the Golden Gate leech\u00a0arrived<\/a> in San Francisco Bay sometime in the 1850s by hitching a ride on plants or debris shipped in from South America. While its population size is currently unknown, the species is considered rare because it can only be found in San Francisco, though Hasegawa suspects the leeches are locally abundant based on how quickly he was able to spot them.<\/p>\n

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The globule of an invertebrate has the capability to protract and elongate its body as it inches along. Particularly noteworthy to Hasegawa is the species\u2019 keen parental care and tendency to brood its offspring. Babies will attach themselves to the bellies of their parents, who carry them to their meals. The leeches primarily feed on flies,\u00a0bloodworms and snails, using their proboscises like a whip to pierce their prey and suck out their fluids.<\/p>\n

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\u201cIt\u2019s interesting to think such a small, kind of primitive creature takes care of its young like that,\u201d he said.\u00a0<\/p>\n

\"View<\/p>\n

View of Mallard Lake in Golden Gate Park in San Francisco.<\/p>\n

Screenshot via Google Street View<\/p>\n

Ultimately,\u00a0Hasegawa considers his discovery a matter of luck and timing \u2014 it\u2019s not uncommon for people on iNaturalist and similar platforms to try to record species that have gone unnoticed. \u201cIn this case,” he said, “I happened to be the first person to get to this one.”<\/p>\n

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Still, he considers it a reminder of how fragile ecosystems can be, and how unique species are in terms of where they can be found. \u201cIt\u2019s cool to see they\u2019re still present to this day,\u201d he said.\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"As the fog burned off on a recent April afternoon, Richard Hasegawa made his way along the southern…\n","protected":false},"author":2,"featured_media":664247,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[51],"tags":[79,245643,201],"class_list":["post-664246","post","type-post","status-publish","format-standard","has-post-thumbnail","category-wildlife","tag-science","tag-sfglocal","tag-wildlife"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/664246","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=664246"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/664246\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/664247"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=664246"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=664246"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=664246"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}