A baby seal has been found in the grounds of a medieval castle in Lincolnshire after losing its way.

The three-week-old pup was noticed on a riverbank 15 miles from the sea by Michael and Charlotte Poole and their five-year-old daughter Tilly, who named the seal Sid.

They were taking their two dogs for a stroll when they spotted the seal struggling to climb into the grounds of Tattershall Castle, north of Sleaford.

The seal is believed to have got lost as it travelled up the river system while on the hunt for food in the River Bain.

After struggling out of the water, it began hauling itself across fields to the moated 15th-century castle, which is run by the National Trust.

The 25 most remarkable animal pictures of the past decade Show all 25 1 /25 The 25 most remarkable animal pictures of the past decade The 25 most remarkable animal pictures of the past decade 2010: The Moment Bridgena Barnard/WPOTY The 25 most remarkable animal pictures of the past decade 2015: Komodo Judo Andrey Godkov/WPOTY The 25 most remarkable animal pictures of the past decade 2011: Tiny Warm Up Cyril Ruoso/WPOTY The 25 most remarkable animal pictures of the past decade 2014: Touche While studying hummingbird behaviour I noticed that a Sword-billed humminbird (Ensifera ensifera) was chased away aggressively by a Collared Inca (Coeligena torquata) every time his route to its favourite Red Angel Trumpet flowers crossed the territory of the Collared Inca. This happened various times until apparently the sword-billed hummingbird decided to his sword for attack and not for feeding. Jan Van Der Greef/WPOTY The 25 most remarkable animal pictures of the past decade 2014: Hollywood Cougar A camera trap photographs P22 strolling down a path in Griffith Park, home to the world famous Hollywood sign. This cougar is studied and monitored by biologist from the National Park Serviceâs Santa Monica National Recreation Area. The catâs ability to remain invisible in such a highly populated area speaks to the stealthy nature of the species. To reach the park, which has been P-22âs home for the last two years, he had to cross two of the busiest highways in the U.S., Highway 101 and the 405. Steve Winter/WPOTY The 25 most remarkable animal pictures of the past decade 2018: Bear Hug This past summer I visited Lake Clark National Park in Alaska, to photograph Alaskan brown bears. Having photographed a few distant grizzly bears in Wyoming before, I was eager to observe these bears more closely, and I desperately wanted a window into their family behavior. I was lucky enough to watch two separate brown bear sows with spring cubs. I watched them browse for sedge grass in the meadows, forage for clams on the beach during low tide, sleep on the forest edges and most of all, play. The spring cubs were full of energy. This mother in particular was extremely patient with her cubs as they romped around and tried to get her attention. This young cub seemed to think that it was big enough to wrestle mom to the sand. Despite all of its efforts, mom stood firm, but did so with a bit of a smile. I'm sure she was happy to know that this cub was a fighter, as this attitude would serve the cub well as it learned to survive along the Alaskan coast. Ashleigh Scully/WPOTY The 25 most remarkable animal pictures of the past decade 2018: The Golden Couple Marcel Van Oosten/WPOTY The 25 most remarkable animal pictures of the past decade 2010: A Marvel of Ants I spent many days with photographing Leaf Cutter Ants. I know five different anthives in the neighbourhood of a lodge in Costa Rica where i lived 6 months. The nearest hive is about 200 meter far from the lodge, which is ideal to the ants to take a visit to collect the plants and flowers of the garden oftens. The interesting part of the action is that the ants only come out to the surface after sunrise and were the most active at night. I used tripod and one flash to take the photo, from the level of the banana leaf. Baiting: none. Bence Mate/WPOTY The 25 most remarkable animal pictures of the past decade 2011: The Assassin Steve Mills/WPOTY The 25 most remarkable animal pictures of the past decade 2019: The Moment Yongqing Bao/WPOTY The 25 most remarkable animal pictures of the past decade 2015: Tale of Two Foxes Don Gutoski/WPOTY The 25 most remarkable animal pictures of the past decade 2016: Entwined Lives An endangered young male Bornean Orangutan climbs over 30 meters up a tree deep in the rain forest of Gunung Palung National Park, West Kalimantan, Indonesia (Island of Borneo). Tim Laman/WPOTY The 25 most remarkable animal pictures of the past decade 2016: Nosy Neighbour Yound urban red fox (Vulpes vulpes) poking its head up over a wall. Bristol, UK. August Sam Hobson/WPOTY The 25 most remarkable animal pictures of the past decade 2017: Pikin and Appolinaire Jo-Anne McArthur/WPOTY The 25 most remarkable animal pictures of the past decade 2018: Mud-rolling Mud Dauber Georgina Steytler/WPOTY The 25 most remarkable animal pictures of the past decade 2013: Mother's Little Headful Udayan Rao Pawar/WPOTY The 25 most remarkable animal pictures of the past decade 2015: The Shark Surfer Thomas P Peschak/WPOTY The 25 most remarkable animal pictures of the past decade 2019: Touching Trust Credit: Thomas P. Peschak/www.thomaspeschak.com Thomas P Peschak/WPOTY The 25 most remarkable animal pictures of the past decade 2017: Memorial to a Species HLUHLUWE UMFOLOZI GAME RESERVE, KWAZULU NATAL, SOUTH AFRICA, 17 MAY 2016: A Black Rhino Bull is seen dead, poached for its horns less than 24 hours earlier at Hluhluwe Umfolozi Game Reserve, South Africa. It is suspected that the killers came from a local community approximately 5 kilometers away, entering the park illegally, shooting the rhino at a water hole with a high-powered, silenced hunting rifle. An autopsy and postmortem carried out by members of the KZN Ezemvelo later revealed that the large calibre bullet went straight through this rhino, causing massive tissue damage. It was noted that he did not die immediately but ran a short distance, fell to his knees and a coup de grace shot was administered to the head from close range. Black Rhino are the most endangered rhino, HluHluwe Umfolozi is one of the last repositories for these animals, with less than 3000 left in the wild today. (Photo by Brent Stirton/Getty Images Reportage for National Geographic Magazine.) Brent Stirton/WPOTY The 25 most remarkable animal pictures of the past decade 2015: Shadow Walker Often, urban foxes are seen only as a brief glimpse of movement as they dart from one shadow to the next. I wanted to try and convery this sense of living in the shadows, but in a different way to merely seeing the fox in a dark environment. To do this I wantes to catpure just the shadow of the subject, rather than the animal itself. I set my camera up high on it's tripod, so that I would see the houses and night sky beyond, but also so that I could ensure the fox would not be in the frame. I positioned the flash gun low to the floor. The idea was for the image was that upon first look you would almost think it's just a silhoueete, but upon further viewing, would realise it was a shadow of the fox as it walked across my decking. SETTINGS: Nikon D810, 18-35 G lens, 32mm, 30seconds, f8, ISO 1250., GITZO tripod, RRS BH-55 ballhead, Camtraptions PIR sensor, Nikon SB800 flash LOCATION: Surrey, UK. PROCESSING: Adjust for the slight perspective shift from having the lens up high, pointing downwards to capture the shadow witout the fox in frame. Localised white balance and exposure work to balance the night sky and flash, and compensaute for the high flash power required to make the shadow as defined as possible. Richard Peters/WPOTY The 25 most remarkable animal pictures of the past decade 2016: Eviction Attempt Ganesh H Shankar/WPOTY The 25 most remarkable animal pictures of the past decade 2011: Still Life In Oil Fort Jackson, Louisiana (USA). June 20, 2010. Volunteers of the Tri-State Bird Rescue and Research and the International Bird Rescue Research Center run the facility in Fort Jackson, Louisiana , where they clean birds covered in oil from the Deepwater Horizon wellhead. The BP leased oil platform that exploded on April 20 and sank after burning. Photo by Â© Daniel Beltra/Greenpeace. Daniel Beltra/WPOTY The 25 most remarkable animal pictures of the past decade 2018: Bed of Seals Cristobal Serrano/WPOTY The 25 most remarkable animal pictures of the past decade 2019: Land of the Eagle Audun Rikardsen/WPOTY The 25 most remarkable animal pictures of the past decade 2011: Boy Meets Nature Location: North Blackfoot Valley, northern Montana, USA Date and time: 7 August 2010, 21:58 Scientific name: Long-legged Myotis (Myotis volans), Satin moth (Leucoma salicis), and a human In a substitute for a bedtime TV, photographerâs son, Victor, is standing on his bed, mesmerized by a fairytale scene of bats hunting huge white moths outside of his cabin window in the North Blackfoot Valley, Montana, USA. He was born in this cabin 13 months before. For a few nights in mid-August, swarms of satin moths (Leucoma salicis) â an invasive moth that came to North America from Europe with timber shipments in 1920s â are attracted to a lone window light. For several nights, local bats (Long-legged Myotis, Myotis volans) flutter around the windows, trying to scoop the moths. Handheld camera wirelessly controlling three remote flashes set at a very low (1/32) output â one above the cabin window pointing down and two inside the cabin. Exposed for warm light given by old desk lamp. Technical details: Canon EOS-1DMark IV with EF 24-105, 1/200 at f/14, ISO 320. Alexander Badyaev/WPOTY

Mr Poole said: “This is one walk we will always remember. It was only when we got closer that we noticed the seal in the water. It was distressed because of the weir which meant it couldn’t get any further.

“It didn’t know what to do but it somehow managed to climb on to the bank although you could tell it was struggling. It looked exhausted. Once it came out of the water towards us it went into a field and headed towards a steep-banked dyke. I blocked its path to stop it because it didn’t think it would get out. It tried to bite me and hissed at me.

Sid the seal in Lincolnshire (SWNS / Jack Evans)

Sid the seal in Lincolnshire (SWNS / Jack Evans)

“It was using its flippers to propel itself forwards. It was most bizarre. A young seal was the last thing we expected to see here.”

The family then called the RSPCA, who rescued the seal pup on Boxing Day and transported it to East Winch Wildlife Centre in King’s Lynn, Norfolk.

Mr Poole, a project manager from Coningsby, said there was “silence on the other end of the phone” when he told the RSPCA where they were.

He added: “I don’t think they really believe it. The seal must have swum up the Witham from the Boston and The Wash and then into the Bain. It must be 15 miles – and all against a flood tide. We were astonished.”

Kate Burris, the RSPCA inspector who rescued the seal, said: “It was definitely unexpected to be contacted about a seal pup at Tattershall Castle. The people who spotted him and called us couldn’t believe what they were seeing.

“The poor pup was trying to get into a small dyke when they noticed him. We think he had come down the weir and climbed up the bank.

“He’s a male grey seal and aged around three-weeks-old. He came in very underweight, at just 14kg, but is doing well. He’s very feisty and has been on fish soup until today when he started on whole fish.”

The seal will be with them for a few months because the release weight for seal pups being returned to the wild from their specialist wildlife centres is 40kg, she said.

In September, a one-month-old seal pup was noticed on a cliff in Pembrokeshire by a member of the public who got in touch with the RSPCA.

“This was quite an unusual place to find a seal as she must have travelled some distance and up a steep incline to get there,” Ellie West, RSPCA animal collection officer, said. “However she got there, she was very much lost and unsure where she was going.”