Mastiff has high obesity risk, needs regular exercise and food control to maintain healthy weight.

Sealyham Terrier has average risk of obesity, needs daily walks and quality diet to maintain healthy weight.

Unfortunately, the Mastiff is not hypoallergenic, making it not a good choice for a dog lover who suffers from pet allergies.

While no dogs are truly 100% hypoallergenic, Sealyham Terriers are about as close as it gets, making them an ideal pet if you are an allergy sufferer.

Affectionate
Cheerful
Intelligent
Protective
Alert
Courageous
Loyal

Alert
Outright
Tempered
Friendly
Calm
Fearless
Intelligent

Mastiffs are moderate shedders, but regular brushing can reduce shedding and maintain coat health.

Sealyham Terriers shed very little hair, making them a great choice for those who dislike excess hair in the house.

Choose a Mastiff if you want a top-notch watchdog. This breed takes guarding seriously, and may not require much training, though obedience or guard dog training can improve their skills.

Sealyham Terriers are decent watchdogs - they'll alert their owner if something seems amiss.

England

Wales

Molosser-type Dogs

corgi, west highland white, wirehaired fox, and bull terriers

American Canine Registry
American Kennel Club
America's Pet Registry
Canadian Kennel Club
Dog Registry of America Inc.
Federation Cynologique Internationale
Kennel Club of Great Britain
North American Purebred Registry, Inc.
American Canine Association, Inc.
Australian National Kennel Council
Continental Kennel Club
National Kennel Club
New Zealand Kennel Club
United Kennel Club

American Canine Registry
American Kennel Club
America's Pet Registry
Canadian Kennel Club
Dog Registry of America Inc.
Federation Cynologique Internationale
Kennel Club of Great Britain
North American Purebred Registry, Inc.
American Canine Association, Inc.
Australian National Kennel Council
Continental Kennel Club
National Kennel Club
New Zealand Kennel Club
Club Espanol De Terriers

Working (AKC:1885)
Guardian Dog (UKC)

Terrier (AKC:1911 & UKC)

Brown

Brown

Black

Black

Cream
Fawn
Brindle

White
Pied
Cream
Brown
Blue

Mastiffs have short coats.

Sealyham Terriers have medium-length coats.

Straight

Wiry

A Mastiff can have a litter of 10-12 puppies on average. However, it's worth noting that the size of the litters can vary greatly. Factors that can influence litter size include the health of the mother, breeding history, and genetics.

A Sealyham Terrier can have a litter of 14-16 puppies on average. However, it's worth noting that the size of the litters can vary greatly. Factors that can influence litter size include the health of the mother, breeding history, and genetics.

Mastiffs typically have low vet costs due to their good health, but it's important to monitor their health and seek vet care when necessary.

Sealyham Terriers are susceptible to health issues like all breeds, so it's important to monitor their health and seek veterinary care when needed.

Gastric Torsion
Hip Dysplasia

Usually A Very Healthy Breed

Entropion
Ectropion
Elbow Dysplasia
Progressive Retinal Atrophy
Retinal Dysplasia
Hypothyroidism

Retinal Dysplasia
Lens Luxation

Eye
Hip
Elbow
Thyroid Tests
X-Rays
Eye Examination

Eye
Hearing
Eye Examination

Mastiffs are a good choice for a low-key lifestyle due to their low energy levels.

Sealyham Terriers' high energy levels make them unsuitable for a low-key dog, choose accordingly.

Mastiff has average social needs and is less independent than other breeds.

Sealyham Terrier has below average social needs and is content with spending time alone.

Mastiffs need only a small amount of physical activity, ideal for busy or elderly people or those with limited space.

Sealyham Terriers need moderate physical activity and are great for families and active individuals.

Mastiffs are known for their relaxed and calm nature and enjoy long periods of sleep.

Sealyham Terriers sleep less than other breeds but still need adequate sleep for good health.

Mastiff excessively drools, consider a different breed if not appealing.

Sealyham Terrier is an average drooler, monitor for excessive drooling which may indicate health issues.

Mastiffs are typically quiet and only bark when needed, such as to alert their owner or when in distress.

Sealyham Terriers bark moderately when necessary and may also bark due to certain triggers like fear, alarm, boredom, greeting, separation anxiety and compulsive barking.

Mastiff dogs are highly protective and make excellent guard dogs due to their strong instinct to defend their territory and owners, and their high level of vigilance.

Sealyham Terrier dogs have a strong protective nature and territorial instinct. They are highly vigilant and will fiercely defend their home and family.

There's really no limit to how far you walk your dog as long as they're comfortable. For Mastiff, it's at least 15 miles / week. Just remember to build distance and stamina gradually over time.

There's really no limit to how far you walk your dog as long as they're comfortable. For Sealyham Terrier, it's at least 6 miles / week. Just remember to build distance and stamina gradually over time.

In general most Mastiffs usually need at least 60 minutes of exercise daily. This can be spread across the day and include all sorts of high-energy activities, like walking, running and playing.

In general most Sealyham Terriers usually need at least 30 minutes of exercise daily. This can be spread across the day and include all sorts of high-energy activities, like walking, running and playing.

The Mastiff has low grooming needs and is easy to maintain.

The Sealyham Terrier requires an average amount of grooming compared to other breeds.

Pin Brush
Nail Clipper

Comb
Deshedder
Scissors
Nail Clipper

For an average 170-230 pound (77 - 104 kg) Mastiff feed 8.5 cups daily. But, keep in mind, the amount you feed is going to be dependent on the quality of the food you are feeding.

For an average 23-24 pound (10 - 11 kg) Sealyham Terrier feed 0.8 cups daily. But, keep in mind, the amount you feed is going to be dependent on the quality of the food you are feeding.

The average cost of a Mastiff is somewhere $8.40 - $9.10 per day.

The average cost of a Sealyham Terrier is somewhere $1.20 - $1.40 per day.

The average per month expenses of a Mastiff is between $252 - $273. This makes an average of $3024 - $3276 per year. It will be on the higher side when the dog is still small because it will need more frequent visits to the vet, shots.

The average per month expenses of a Sealyham Terrier is between $35 - $42. This makes an average of $420 - $504 per year. It will be on the higher side when the dog is still small because it will need more frequent visits to the vet, shots.

Mastiffs are average in obedience intelligence but have a high IQ and may cause trouble if left unsupervised.

Sealyham Terrier has below average obedience intelligence, but they excel in understanding human emotions.

Mastiffs have average emotions and adapt well to different situations.

This breed is sensitive and requires gentle handling and a calm home environment.

Mastiffs are good apartment dogs as long as they get enough exercise and stimulation outside of the apartment.

Sealyham Terriers make excellent apartment dogs, being fairly active indoors and not requiring a yard.

Mastiffs make excellent family pets for kids due to their gentle, protective nature and calm temperament.

Sealyham Terriers are good with kids if socialized and trained from a young age.

Mastiffs are very friendly with cats and make great companions for them.

Sealyham Terriers are average in their friendliness toward cats and tend to do well with them, especially if raised together.

Mastiffs are average in their friendliness towards other dogs, and socialization can help.

Sealyham Terriers are friendly and active companions, and can be good family pets, though their friendliness towards other dogs may vary.

Mastiffs are not known for being a highly playful breed.

Sealyham Terriers have an average level of playfulness, enjoying playtime like most dogs but not excessively so.