Pet Care Blog

Rat Terrier Growth & Weight Chart

Dr. Lila Batiari
Small Animal Relief Veterinarian
rat terrier on a big rock

The Rat Terrier’s name is commonly linked to President Theodore Roosevelt, who took these dogs hunting with him. In the early 1900s, they gained popularity for their exceptional ability to control vermin. Bred as agile and muscular farm dogs, Rat Terriers were specifically tasked with keeping properties free of rats and other pests.

Today, they are beloved family pets known for their energetic and playful demeanor. Rat Terriers come in two distinct sizes, miniature and standard — and their smooth, shiny coats often feature striking pied patterns, making them an elegant yet sturdy breed.

Like all dog breeds, Rat Terriers experience distinct growth phases that owners need to recognize to support their healthy development. Familiarizing yourself with these growth patterns, from their early puppy days to adulthood, is essential for tracking their health and size. This article will explore their developmental milestones and cover common questions, such as how much to feed a puppy.

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Male Rat Terrier Growth & Weight chart

Male Rat Terriers generally experience a steady growth phase during their first year. The miniatures are smaller and tend to mature earlier, while standard Rat Terriers take a bit longer to reach their full size. Below is a growth chart that provides an estimate of what you can expect from your male Rat Terrier at various stages of development:

Age (Months)

Weight (Pounds)

Height (Inches)

2

2 - 4

5 - 7

4

5 - 8

7 - 9

6

8 - 12

10 -12

9

10 - 18

12 -15

12

12 - 25

13 - 18

Female Rat Terrier Growth & Weight Chart

Female Rat Terriers tend to be smaller than males, though their growth patterns are similar. Like the males, miniature females will mature earlier than standard-sized females. Here's an estimate of their growth at different stages:

Age (Months)

Weight (Pounds)

Height (Inches)

2

2 - 3

5 - 7

4

4 - 7

7 - 9

6

7 - 11

10 -12

9

9 - 16

12 - 14

12

10 -23

13 - 16

When do Rat Terriers stop growing?

Rat Terriers, both males and females, typically reach their full height between nine and 12 months of age. Miniature Rat Terriers tend to stop growing a bit earlier, usually around nine months, while standard-sized Rat Terriers may continue to grow slightly beyond their first birthday. After they have reached their full height, they may still gain some weight and muscle mass, usually completing their growth cycle around 12 to 18 months.

It's essential to note that growth can vary depending on the individual dog. Some Rat Terriers may grow faster, while others may take more time. Regardless of the pace of growth, by the time your Rat Terrier reaches 12 months, they are likely to have achieved most of their physical maturity.

How much bigger will my Rat Terrier get?

If you're wondering how much more your Rat Terrier might grow, looking at their current age and weight is helpful. By six months, most Rat Terriers have reached around 75% of their adult size. If your dog is nearing the top end of the growth chart for their age, they are likely close to their full size. They may have more growing to do if they are on the smaller side.

Factors such as diet, exercise, and genetics all play a role in determining how big your Rat Terrier will get. A well-balanced diet and plenty of exercise are crucial to supporting healthy growth. You can also check with your veterinarian if you are concerned about your dog's growth rate. They can help determine whether your dog is growing as expected for their breed and size.

What is the size of a full-grown Rat Terrier?

Full-grown Rat Terriers will fall into one of two categories: miniature or standard.

Miniature Rat Terriers: Stand between 10 and 13 inches tall at the shoulder and typically weigh between 10 and 18 pounds.

Standard Rat Terriers: Stand over 13 inches tall, reaching 18 inches in height, and weigh between 18 and 25 pounds.

Both types of Rat Terriers are known for their lean, muscular builds. Despite their relatively small size, these dogs are sturdy, agile, and capable of long periods of physical activity. Their sleek, shiny coats and balanced frame give them a stylish yet rugged appearance.

Rat Terriers' compact size makes them excellent companions for apartment living and homes with yards. Their manageable size and high energy levels make them adaptable to different lifestyles as long as they get enough exercise and mental stimulation.

rat terrier lying down

How do I make sure my Rat Terrier is healthy?

Ensuring your Rat Terrier remains healthy throughout their growth phase and into adulthood requires attention to their diet, exercise, mental stimulation, and regular veterinary care.

Proper diet

A balanced diet is crucial for healthy growth. Your Rat Terrier should eat high-quality dog food appropriate for its age, size, and activity level. Puppies require food that supports growth and is rich in protein and essential nutrients. As they transition into adulthood, it's vital to feed the dogs a diet that maintains their lean body mass without encouraging excess weight gain.

Monitor their portion sizes to avoid overfeeding, as Rat Terriers can be prone to obesity if not given the proper balance of nutrition and exercise.

Regular exercise

Rat Terriers are energetic dogs that need regular physical activity to stay healthy. Aim for daily exercises, whether it's through walks, playtime, or engaging activities like fetch. Lack of exercise can lead to boredom and destructive behaviors, so keep them physically and mentally stimulated.

These dogs also excel in agility sports and enjoy having a "job" to do. Whether hunting, training for agility courses, or interactive play, keeping their minds and bodies active will help them stay healthy.

Mental stimulation

In addition to physical exercise, Rat Terriers need plenty of mental stimulation. Interactive toys, puzzle games, and obedience training can help engage their minds and keep them from boredom.

Regular veterinary check-ups

Routine vet visits are essential for keeping your Rat Terrier in top health. Regular check-ups can help catch potential health issues early, ensure they are on track with their growth, and keep up with vaccinations, parasite prevention, and dental care. Also, monitor their weight and make necessary dietary adjustments as they transition from puppyhood to adulthood.

Ahead of your vet visits, we recommend investing in pet insurance for financial protection against unexpected health issues in dogs, such as accidents and surgeries. Additionally, consider securing a wellness plan to help cover vet visit costs for essential services, such as vaccinations, vet exams, microchips, and more.

You can find the perfect plan for your pet on Pawlicy Advisor, which is designed to save you money over your pet’s life by compiling and comparing personalized policy recommendations for free.*

*Note, our figures are estimates, and so we recommend speaking to a veterinarian to get a more accurate assessment of their pet’s health and growth potential.

Socialization

Rat Terriers can sometimes be wary of strangers or other dogs, so socialize them from a young age. Exposing them to people, pets, and environments will help them grow into well-adjusted, confident dogs. Puppy training classes or group play sessions can also help reinforce good behavior and social skills.

Final thoughts

Rat Terriers are a unique breed known for their energy, agility, and strong hunting instincts. Whether they belong to the miniature or standard category, understanding their growth and weight patterns can help you ensure they develop healthily. By providing them with a balanced diet, regular exercise, mental stimulation, and routine vet care, you can help your Rat Terrier thrive throughout their life.

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Dr. Lila Batiari, DVM

Dr. Lila Batiari
Small Animal Relief Veterinarian

Lila Batiari, DVM is a relief veterinarian located in San Diego, California. She has a special interest in nutrition, pain management, and surgery! Dr. Batiari enjoys working with Pawlicy Advisor to help others avoid everyday situations that some of her clientele experience. She realizes that expensive vet bills for treatment costs could be much easier for patients with pet insurance.

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