His fascination with the species has since taken him all over Scotland, including its most northerly outposts in Shetland, and as far afield as Canada.
Capturing their activities on camera has required a lot of watching and waiting, but the results, seen in his new book The Secret Life of the Otter, show his efforts have been well worth it.
Howard explains the connection he feels to the species.
“Otters are fascinating in both the details of their life and their character,” he says.
“Born killers, the mothers are loving to their offspring, so tender their emotions can seem almost human.
“Their liquid movement in water is as balletic as it is purposeful, but their movement on land, while quick and effective, is so different it could belong to another species.
“They do comic things, playing with each other, with pieces of seaweed, fish, crabs.
“Their antics and mischievous ways never fail to bring a smile to my face and when I am closely observing them at rest… is that a form of kinship I feel?
“Like the otter I am endlessly curious and live a restless life.
“Like the otter I am completely focused on my purpose.
“Like the otter I am dead to the world when I settle for the night and, often, when I watch them sleeping, my breathing will co-ordinate with theirs until I too start to drift.”
But Howard warns that otters, despite their cuteness and appeal to nature-lovers, can be fearsome creatures.
He says: “For all its attractions and human-like qualities the otter is a wild animal – intelligent and playful, but sharp-toothed and quicker than any human hand can hope to be.”
Introducing the book, renowned wildlife filmmaker Gordon Buchanan has high praise.
He says: “Prepare to be spellbound. Let this foreword act as a somewhat inadequate drum roll for a breathtakingly beautiful experience, the most delightful and definitive portrait to date of this wonderful animal.”
He concludes: “Among these pages is the generous gift of lived experience, including moments of intimacy, revelation and joy, as Andy Howard gradually reveals the secret life of the otter.
“Absorb, as deeply as you can, every visual image and written word of this marvellous portrayal.
“It will prove to be a rare experience and will live with you for many years.”