Sue McDonnell, PhD, Certified AAB

Sue M. McDonnell, PhD, is a certified applied animal behaviorist and the founding head of the equine behavior program at the University of Pennsylvania's School of Veterinary Medicine. She is also the author of numerous books and articles about horse behavior and management.

Articles by Sue McDonnell

Sleeping Patterns

I think my 11-year-old mare isn't getting enough sleep. My mother and I have seen her start to fall asleep in her paddock and in her stall during the day. Her eyes begin to close, her lower lip hangs loose, and her head slowly lowers. When it Read More

Using the Twitch Properly

I attended a short course on horse behavior at New Bolton Center where you explained how a twitch works and your recommendations for how to use it most effectively. It seemed to make so much sense why sometimes it works and sometimes it doesn't, Read More

Spooking on Trail

I have a 17-year-old Arabian mare. When trail riding, she looks for every opportunity to jump, spook, or take off, especially now that my other horse, her companion, no longer accompanies her. The companion is 30 years old, and due to a recent Read More

Water Crossing

How can I get my horse to cross through water when I'm riding him on trail? He refuses to even get his feet wet.           via e-mail


For horses that are afraid Read More

Breaking A Young Horse

My husband and I recently broke my 3-year-old mare to ride. The first few times she rode like a dream, then she caught on to the idea that when we catch her, she has to work, and she has gotten a bad attitude. Her new antics include bucking. I'v Read More

Taming an Aggressive Foal

We recently were blessed with a healthy filly. However, the breeder we bought the mare from had her due date wrong. She came five weeks before we were expecting her. She was born in the pasture with another mare present. Th Read More

Sleep-Crashing

In any of the equine behavior literature that I have read, I am unable to find any description of the sleeping behavior we see in our retired broodmare (17 years old). She has functioned as the watch horse in the small herd she was from, and she Read More

Blind and Restless

My 19-year-old horse is 95% blind, and when he's not eating or sleeping he walks in circles. What can I do to stop or minimize this behavior? via e-mail


You certainly would want to have this horse evaluated by a Read More

Don't Leave Me Alone!

Why do some horses not like having their buddies taken out of their pen when they have to stay in?    Katy


The ancestors of our domestic horses were open plains grazing animals, for whom the strategy Read More

Get a Vet!

When I ride my 24-year-old Arabian mare Western, she tends to want to pick up the pace and wants to look around. How can I get her to slow down and stay focused? She gets stiff and starts to limp on her left hind leg when I am riding her. Anothe Read More

Play Invitation

We have been struggling with a very particular behavior problem with a young colt. From birth, he's been a strong and athletic rascal, and has been "full of himself," with the usual colt behavior tendencies. We have dealt successfully with all Read More

Foals and Geldings

My 12-year-old daughter's 9-year-old Welsh Pony gelding (named Taffy) was moved to a new stable about eight weeks ago. Six weeks after the move, Taffy was introduced to the mares and allowed to graze and socialize with them. Since four of the 16 Read More

Handling a Hostile Broodmare

My mare just had a colt today and I have a concern about it because she is 13 years old and not broken. She had been broken three times prior to me getting her, and she won't come near anyone. My question is: How will I be able to mess with the Read More

Bereavement Leave?

I have two horses in my stable yard. One is a 20-year-old retired ex-chaser gelding and the other is a 12-year-old Arab gelding. They have been together for seven years, six of which were spent living on a small yard with just the two of them an Read More

Hauling Training

I'd like recommendations for safe hauling for weanlings. What's the easiest way to proceed for happy hauling? Read More

Sudden-Onset Headshaking

My pony started tossing his head and cribbing at about the same time. The head tossing has increased to the point of not being able to ride him. He has had his teeth floated and has been checked by a vet for common problems. He has never had Read More

Fear of Cows

My horse is a 16.3-hand 7-year-old off-track Thoroughbred. His history is largely unknown. My problem is that in the five months I've had him at a boarding stable, he hasn't gotten over his fear of cows and their field, which is about 10 fee Read More

Abusive Training for Stud Colts

I hope you are not offended by this question, and that you will find time to answer it if you know anything about it or maybe could refer me to someone else who might have heard of this fairly unusual advice. My boyfriend was afraid to write Read More

Tail Rubbing

One of our mares rubs her butt on everything, all the time. It messes up the top of her tail, and she always has these big scratch marks across her butt.

We can't seem to get her to stop it. We have dewormed her regularly and Read More

Picking a Children's Pony

One of the fondest memories I have as a very young child is hugging and brushing a pony that our neighbors had, and I had always wanted to have one of my own. Our daughter is 3 1/2 years old and we are expecting our second child, a boy, in Read More

Tough Catches

I have an 18-year-old Tennessee Walking Horse that was vaccinated two weeks ago with no apparent reaction. A w Read More

Understanding Male Aggression

I purchased my horse a year ago knowing he had some aggression problems. He is great around people, just not around other horses. Unfortunately, when he attacks, he goes for the throat just behind the jaw line. He refuses to let go at times, Read More

Can't He Just Drink Out of It?

There are several possible explanations as to why a horse might play with his water bucket every night. Read More

Slow-Starting Stallion

We just started using a 3-year-old Quarter Horse stallion for breeding. He is sort of interested and will rub his head on the mare a bit, but he drops about half-way, then up, down, up, down. He doesn't seem shy or anxious, just lazy, like a Read More

Follow-Up: Carnivorous Horses

Last October, we shared letters from three readers describing horses killing and/or eating small mammals and birds (see "Carnivous Horses," article #3832 at Read More