meet Our team of certified trainers and experienced behavior technicians

Ursa and Niko

Ursa and Niko

Ursa Acree, CPDT-KSA, CDBC

CO-OWNER and behavior consultant

Ursa Acree is a Certified Professional Dog Trainer, Knowledge and Skills Assessed, an IAABC Certified Dog Behavior Consultant, and a Certified Fear-Free Trainer, originally from Louisville, Kentucky. Ursa began training in 2001 after getting her first "very own" puppy, Ruckus, a Belgian Tervuren mix. After she and Ruckus attended dog training classes together, Ursa was asked by the instructor if she would be interested in apprenticing - and she was. 

She soon began teaching group classes for a local chain of pet stores, offering basic through advanced obedience, Rally-O, nose work, and Canine Good Citizen classes. She was noticed by the Board of Directors of the Kentucky Humane Society, who hand-picked her to fill the recently vacant Behavior Manager position. Over the next four years, Ursa was tasked with growing KHS' external behavior department - responsible not only for bringing in revenue for the shelter, but also preventing pets from being relinquished for behavior problems. Working with thousands of dogs a year in group and private settings, she also earned her CPDT-KA in 2007. 

In 2010, Ursa was hired as the Behavior Manager for the Dumb Friends League in Denver, Colorado. With eight full-time staff and over a hundred volunteers, she oversaw nearly a dozen behavior programs designed to help relinquished dogs, cats, and other pets overcome behavior issues to make them more adoptable. With an intake of nearly 25,000 animals annually, she and her staff worked with nearly every imaginable behavior issue.

In 2013, Ursa and her family moved to Kansas to pursue the opportunity to own a farm. Meanwhile, she took a position with Hill's Pet Nutrition as a Behavior Research Technician at their nutritional research facility in Topeka, Kansas. There, she and the Behavior Team were responsible for the behavioral health and training of nearly 500 dogs, including husbandry, enrichment, behavior modification, and teaching scent and taste discrimination tasks. 

But, Colorado loomed large in their hearts, and in 2015 the Acrees returned to Denver, where Ursa now spends her time helping dog owners in their homes. While her passion is working with aggression, reactivity, and fear, she ultimately loves helping all owners make a connection with their dogs and to see them begin communicating in the same "language."

Ursa is, and always has been, committed to force-free methods, training without the use of fear, pain, or coercion. She believes in emphasizing and reinforcing desired behaviors, rather than waiting for dogs to make mistakes. By creating an environment in which dogs are eager to learn without fear, and incorporating reinforcement into everyday life, good behavior becomes a habit rather than a chore.

Ursa is a member in good standing of the Association of Professional Dog Trainers and the Pet Professional Guild, and is currently pursuing CBCC certification. She was also the first Certified Fear-Free Trainer in Colorado.

Kimberly and a shelter puppy

Kimberly and a shelter puppy

Kimberly McRae, CPDT-KA

Co-owner and behavior consultant

Kimberly is a Certified Professional Dog Trainer, Knowledge Assessed, Certified Fear-Free Trainer and an AKC Approved CGC Evaluator , originally from New Albany, Indiana. Her passion for animals and learning theory has propelled her into a life of helping others understand how to communicate with their dogs.

Kimberly's initial exposure into dog behavior modification began with the adoption of her first dog, a 4 month old German shepherd mix in 2005.  She was eager to understand why her puppy would develop reactivity to other dogs while on leash and fell in love with training while taking classes and volunteering at the Kentucky Humane Society.  

Kimberly also worked as a Training and Behavior Coordinator for the Humane Society of Boulder Valley, helping to enrich the lives of dogs in the shelter and address behavior issues to increase adoptability.

Over the years, Kimberly has studied the methodologies of industry leaders in positive reinforcement and behavior, committing to the humane hierarchy for behavior modification and training. In addition, She is a member in good standing of the Association of Professional Dog Trainers and the Pet Professional Guild. She believes empowerment, for both animal and handler, is a critical piece for changing behavior ethically and enjoys teaching individuals about advocacy.

Kimberly has a Bachelor's Degree in Biology from Indiana University. Kimberly resides in Denver, CO, with her dogs Gixxer, Taco, and Hazel and spends downtime doing outdoor recreational activities.

Helena and Boo

Helena and Boo

helena kokes, acdbc

trainer & behavior consultant

With over 12 years of animal behavior and training experience, Helena brings a drive for finding solutions that fit each client's lifestyle and goals. Keeping in line with the latest scientific research from The International Association of Animal Behavior Consultants, The American Veterinary Society for Animal Behavior, and the ASPCA, Helena achieves real-life results through positive reinforcement based training for both people and animals, enriching lives while solving problems.

Specializing in fear, aggression, and other disruptive behaviors, Helena pulls from her extensive shelter behavior background, working with both dogs and cats to solve behavior issues with limited time and resources. In addition to currently serving as a Training and Behavior Consultant for the Humane Society of Boulder Valley, Helena served in the Dumb Friends League Behavior Department where she ran the behavior hotline, taught classes, and trained other staff and volunteers. 

Helena is an Associate Certified Dog Behavior Consultant with the IAABC, and she has spoken to other professionals on numerous occasions, sharing her knowledge of behavior at conferences and lectures for The Interdisciplinary Forum for Applied Animal Behavior, The Humane Society of the United States, and The Colorado Federation of Animal Welfare Associates. 

Mariah Dingus

trainer & behavior consultant

Like all of us here at Canis Major, Mariah grew up with a deep compassion for animals. She could be found either at the barn with her horses or training her Coton de Tulear in agility on a regular day. Mariah always knew she wanted a career working with animals and started acquiring professional experience through her keeper aid positions at the Houston and Cheyenne Mountain Zoos throughout high school and college, where she trained animals from rhinos to grizzly bears to participate in cooperative vet care. However, it wasn’t until Mariah’s internship at the Penn Vet Working Dog Center that she discovered canine behavior and training was her true passion. There, she trained dogs to be experts in ovarian cancer detection, search-and-rescue, and dual-purpose law enforcement, all while staying committed to force-free methods.

Mariah expanded her knowledge of applied animal behavior through an externship with certified veterinary behaviorist Dr. Lore I. Haug. In this role, Mariah assisted in addressing behavior cases from generalized anxiety to human aggression, honing her skills in identifying behavior problems and how to solve them benevolently and from the source, in the best interest of both dog and owner.

Mariah has a Bachelor’s Degree in Biology from Colorado College. When she is not training, you can find her hiking in the mountains, trying new recipes in the kitchen, or soaking up a new book in front of the fire or by the pool (seasonally dependent).

Mariah is currently pursuing her CDBC certification from the International Association of Animal Behavior Consultants.


Tessa and Bindi

Tessa and Bindi

Tessa burman, KPA-Ctp

operations coordinator & dog trainer

Tessa’s passion for “all things dog” began in her early childhood, but it wasn’t until she enrolled in Karen Pryor’s Dog Trainer Foundations course in 2015 that she began to consider a professional career working with animals. After completing the introductory course and officially catching the “training bug”, she decided to continue her education by enrolling in the Karen Pryor Academy Dog Trainer Professional Program. She graduated with distinction in 2017 and now holds the title of Karen Pryor Academy Certified Training Partner.

Prior to joining the Canis Major team, she spent two years working at the Humane Society of Boulder Valley, first as an Adoption Specialist and then as a Training and Behavior Consultant. During her time at HSBV she had the pleasure of coordinating all administrative duties for the training department, teaching group classes, and working one-on-one with clients to help them better understand and communicate with their dogs. Tessa is passionate about the life-changing effect pets can have on their people and is committed to using humane and science-based training techniques to help promote that bond.

When she’s not spending time working with and training other people’s dogs, Tessa enjoys training and spending quality time with her own dog, a lab mix named Bindi.

Ali and Bodhi

Ali and Bodhi


Trainer & Behavior technician

Ali adopted a rescue dog that was severely fearful and under-socialized. Learning how to best help her new dog, Bohdi, be happy and comfortable in the world started a whole new passion-turned-career of working with dogs and their families. Her education took place at the prestigious Pat Miller Academy in Maryland where she learned reward-based, force-free training and behavior modification. She continues to improve her skills and enjoys volunteering at the Humane Society of Boulder Valley, helping dogs who would have a difficult time getting adopted without some training intervention. With a Bachelors in Communication and previous work experience, Ali is excellent at building relationships with people as well. Combined with her skills with dogs, this creates a unique ability to build the parent/dog understanding.

In her free time, you can find Ali and Bohdi engaging in the sport of Nose Work. This hobby is a fun and enriching activity where handlers support their teammate dog in their natural drive of hunting scent.

Shannon and her foster puppy

Shannon and her foster puppy

Shannon villatoro

behavior technician

Shannon’s affinity for animals began as a child when her family adopted a former puppy mill breeding dog. By the age of 16, she was caring for dogs and cats at a veterinary clinic. From there, she accepted a position at the Dumb Friends League animal shelter, working in many capacities including husbandry, assisting with behavior, and veterinary care. She currently works at DFL as a vet assistant.

When she’s not caring for other pets she loves spending time with her two dogs, Feely and Sachi; cats, Jupiter and Massuzie; and rats Coconut and Poppy. In her spare time she also fosters animals who come into the shelter needing a little extra care and attention. Shannon is exceptionally patient and especially enjoys working with fearful dogs to help them come out of their shell.

bettina schaden

Behavior Technician

Bettina and Presta

Bettina and Presta

Bettina’s passion for training was awakened after the adoption of her first dog, a spunky boxer mix named Presta Button. While helping Presta overcome her challenges, Bettina learned about the incredible power of positive reinforcement. From the very beginning, she has been committed to force and fear-free handling and training.

As a self-starter and learner, Bettina is seeking her training education through numerous seminars, conferences, and as a mentee of talented local trainers. She is inspired by the body of work of luminaries such as Dr. Patricia McConnell, Kathy Sdao, Dr. Susan Friedman, and others. She has completed the Dog Trainer Foundations course offered by Karen Pryor Academy and a Dog CPR, First Aid, and Safety course.

Bettina is a dog walker in Denver and volunteers at the Humane Society of Boulder Valley. She is currently pursuing her CPDT certification.