Sealyham Terrier

Terriers

Small

Median 13.1 y

FCI group 3 · Terriers · Derived from the adult weight midpoint (10 kg)

Median survival across 158 UK dogs (VetCompass, McMillan 2024) · half live 10–15 y

The Sealyham Terrier is a rare Welsh breed of small to medium-sized terrier that originated in Wales as a working dog. It is principally a white-bodied, rough-coated breed, developed in the mid-to-late-19th century by Captain John Edwardes at Sealyham House, Pembrokeshire.

Alert

Outgoing

Calm

Summary from Wikipedia (CC BY-SA) · reference ranges from the Kintail breed dataset

Adult weight

Reference

Male

10–11 kg

Female

9–10 kg

Breed club figure (the American Kennel Club)

Weight for age

Stock data

Male

Female

Expected range

Expected range from the breed's own adult weight, kilograms. Growth reference: Salt et al. 2017, WALTHAM (9–15 kg band).

Heat cycles · females

Stock data

First heat

8–12 mo

typical

Interval

180 d

typical

Bleeding

~9 d

typical

Proestrus 9d

Estrus 9d

Diestrus 52d

Anestrus 110d

General figures for dogs, not for this breed — individual cycles vary widely.

Questions people ask

Adult males usually weigh 10–11 kg and females 9–10 kg. Most are close to their full size by around 18 months, though the last little bit of filling out takes longer. Growth reference: Salt et al. 2017, WALTHAM (9–15 kg band).

No Sealyham Terrier cycle figures are published here yet, so this is general guidance rather than a breed number: most females have a first season somewhere between six and fifteen months, and cycles then settle to roughly every 180 days. Smaller breeds tend to start earlier and larger ones later.

The median is 13.1 y. Median survival across 158 UK dogs (VetCompass, McMillan 2024) · half live 10–15 y. How the later years go comes down to weight, teeth, exercise and regular check-ups far more than to the breed.