Jordi Casamitjana, the author of the book “Ethical Vegan”, interviews Danny Rosenthal, the long-term committed vegan New Yorker who wants to make tennis vegan — because, currently, it’s not quite vegan-friendly yet.
I had no idea.
I thought that, after my twenty years of being vegan, I managed to get rid of all animal products from my home. But I have one item that, not until now has it ever occurred to me that it may not be vegan.
Some years ago, I had a very bad attack of a type of sciatica, causing me pain in my leg. Since then, I have been able to prevent further attacks by doing daily stretching, and by applying pressure to the Piriformis muscle (in my gluteal region, also known as “my bum”) when I feel pain building up. The best way to do that is by using a tennis ball. You lay on the floor, put the ball where the muscle is, and lean on top. After a few minutes of increased pain doing this, normally the pain goes away as the muscle warms up and blood gets to it, healing it.
I found the ball at my local park in London, undoubtedly lost in a human-dog “bring me the ball” game. It looked quite intact and clean, so I decided to take it home to use it for my exercises (remembering my chiropractor’s advice). But now that someone told me that many tennis balls are not vegan, I had to check this out.
Danny Makes Tennis Vegan
I assumed that the times when animal guts were used as strings for tennis rackets are mostly gone. Nylon and other plastics have now replaced them. I also knew that there are vegan-friendly sport shoes now, so tennis shoes should not be an exception. But I never thought about the balls. So, when I googled it and found a campaign titled “Make Tennis Vegan”, I realised this was quite an indicator that tennis balls may not be as vegan as I thought they were. Why? Because it turns out many are made of wool — an animal product rejected by all ethical vegans which comes from a cruel industry that harms sheep and damages the environment.

Danny Rosenthal, an American vegan for almost 30 years, founded this campaign because he cares deeply about sheep. When he learnt that the balls used at competitive-level tennis were made of wool, he created Sheeps Tennis intending to produce vegan tennis balls. But as it seemed to be a too difficult and slow process, he decided to turn it into a campaigning organisation too.
I wanted to check if my tennis ball was one of those that is made of wool and learn how Danny found out that many are not. My colleague Jackie from Vegan FTA put me in contact with him.
From his apartment in Brooklyn, and from my flat in London, Danny and I had a Zoom chat which started, as customary, with me asking him about his vegan journey:
“I’ve been a vegan for about 29 years. I consider myself an animal welfare supporter, an ethical vegan, and I’ve been involved with supporting various vegan related efforts. I believe that I was born to be a vegan, but it took me about 24 years to realise it, unfortunately. I was lactose intolerant, so my body was not accepting dairy and I felt repelled by meat.
I grew up in a household and in a culture that never recognised animal cruelty. I never met a vegetarian or a vegan when I was a young person. The concept just didn’t occur to me. And then, when I was a young adult, I had a girlfriend who had a job as a babysitter. She told me that the mother of the child that she was caring for was a vegetarian. She took a little moment to think about it and said: ‘I’m a vegetarian too’. I took about a day to think about it myself and I said: ‘you know what? I’m a vegetarian too.’ I had this clear understanding of why I felt this way about me and animal food all these years, but I just had never quite made the connection. Once the connection was clear, there was no way I was ever going to retreat. And so, I was vegetarian for a year, after which I became a vegan. About 1991. And in all the years since, I’ve just become increasingly committed to it.”
I asked Danny about his tennis credentials too:
“I’m also a tennis fanatic, so I play tennis. I’m a teaching professional and I’m a coach. I play competitively but not at the professional level. I played rather seriously as a youth and then regrettably I let it go at around the time I went to college. But it was a passion that was always simmering with me. And I always had an idea that I wanted to return to it.
And then about seven or eight years ago I re-encountered the sport as my kids were getting into their teen years, so I found myself with a little bit more discretionary time. I started a club and then I started playing competitively. I’m involved almost daily with something related to tennis, either playing, teaching, or coaching. And I’m also on the board of a couple of tennis organizations. One is involved with bringing tennis to low-income youth. I’m really interested in expanding access to the game. Disabusing the idea that the game is for white affluent people. I’m really interested in universalising the game.”
The Disappointing Discovery
No matter how long you have been a vegan, you will continue to experience the disappointment of discovering that something you have been using for years isn’t vegan after all. Sometimes it is just a matter of interpretation regarding what makes a product vegan enough for you (such as if the company producing it was taken over by another non-vegan company or you discovered it is testing on animals in some circumstances you didn’t know about), but other times is unequivocal (if there is a clear animal product in it, such as honey, whey or wool). When that happens, you have three options: continue using the product reluctantly if you feel you need it and there are no vegan-friendly alternatives for you; stop using it altogether and move on; or attempt to make the product vegan by either contacting the manufacturer or starting a campaign. Danny also had these three options when he made his hugely disappointing discovery.

“It was actually initially related to tennis shoes. About every six months, I go to a sporting goods store in New York City called Paragon. It’s one of the major sporting goods stores around. They have a very large selection of athletic shoes so I go to the sneaker section, and I typically would say: ‘show me your non-leather shoes’. And I would just pick out one of them. Typically, whatever was the least expensive.
For whatever reason, one time about three years ago I said: ‘what tennis shoes do you have that are vegan’. Instead of non-leather I use the term vegan, and the salesperson was surprisingly knowledgeable about it and he kind of smirked at me and said: ‘none of them are vegan’. And I got very upset. And I said: ‘what do you mean? I’ve been buying non-leather shoes here for years’, and he was like: ‘yeah, they’re non-leather but there are animal products in the adhesive and the dyes.’ And that was very distressing for me.
I went on a mad research effort to try to identify entirely vegan shoes. I finally did, not because they were purposefully made vegan or marketed as vegan, but I was able to go through with back channels through somebody I know who’s in the industry to identify a pair of Fila shoes that don’t use any animal products. And I got that verified through the company.
I was satisfied, but along the way, it occurred to me: ‘what about the balls?’ The balls must contain adhesives as well. So, with dread in my heart, I went and researched that, and I found out it was much worse than I imagined. The covering contained wool, so that set off an alarm for me. The problem was worse than I had anticipated. And I was really very upset. I considered quitting the sport that I love. My wife, who’s also vegan, seeing how upset I was, said: ‘don’t quit tennis; you can’t quit tennis, but do something about it.’ I said: ‘of course, you’re right.’ I decided to take it up as a project.”
The New Yorker with a Mission
In addition to his love of tennis, Danny is a long-time consultant to social services, social justice, environmental justice and animal welfare organizations. So, he knew how to campaign. The first thing Danny had to do — as in any campaign of any sort — was research the subject he wanted to campaign about. And he did good research indeed:

“My understanding is that the large majority of balls are non-vegan. That there are a few varieties of balls that are inadvertently vegan because factories choose to use less expensive materials. I’ve learnt about this because I hired a vegan design firm to work with me on this project and we were able to do research. Go into the back channels and speak to representatives at companies that are involved in the manufacturing of the balls and provide the materials. And they were able to identify some balls for us.
Subsequently, I took them to a lab to have them tested and indeed verified that they were vegan. They’re made of acrylic and nylon, not wool. Regrettably, the balls don’t perform as well. They’re a little bit too bouncy. They don’t have the same amount of thickness. I believe that with a little bit of research and development there’s every reason to expect that high performing vegan balls could be produced. It’s just that no one has ever made that intentional effort.”
Danny went into producing vegan tennis balls himself, and although he managed it, he is not totally satisfied yet:
“I have produced balls overseas. I’ve been through a few different series of efforts to try to independently produce the balls. I know that they’re vegan. The problem is they don’t perform well enough. And coordinating with factories in Asia has proven to be extremely difficult and problematic. I’ve tried this with a few different factories, and we’ve never been able to get to a high performing ball. But there were a lot of communication problems and cultural differences. I don’t believe, based on that experience, that the balls can’t be produced. I think there just need to be people involved that are more knowledgeable about it and committed to it.
My hope is not only that we can substitute the wool for vegan materials but that we can create a more environmentally friendly ball. That we can produce a biodegradable ball because these balls would not be particularly good for the environment either. I mean, we obviously eliminate the problem of animal cruelty and factory farming by replacing these balls, but they still don’t decompose properly. They create problems in the landfill and so forth. I did commission a study on the feasibility of producing biodegradable balls and there’s every reason to believe that that’s possible as well.”
Another Type of Vegan Activism

Perseverance and tactical thinking are two of the required skills for good campaigners, and I think Danny qualifies:
“My first intention was to attempt to produce the balls myself and I worked on that for about maybe a year or a year and a half. I tried four different times to work with factories overseas and it did not materialise. After that, I decided that, instead of trying to produce them myself, I would try to pursue an advocacy campaign designed to persuade the existing tennis ball manufacturers to do so.
I published a change.org petition, I hired a public relations firm and I got active on social media. I contacted Wilson, Dunlop, Penn, and Slazenger, and told them about the situation. I asked if I could collaborate with them, or if they would go ahead on their own and explicitly produce vegan tennis balls. No response. I hope that perhaps they’re working on it behind the scenes.
I also contacted PETA, which did a petition calling for all athletic equipment to be made vegan. They got about 25,000 signatures.”
Danny ended up launching the ‘Make Tennis Vegan’ campaign via his company Sheeps Tennis (where you can also find information about vegan-friendly tennis equipment). This is what its homepage says:
“We’re avid tennis players and long-time committed vegans. When we realized that most tennis balls contain wool, a highly problematic material, we became alarmed. In response, we established Sheeps, an activist company on a mission to make tennis vegan. We’re focused on raising awareness about the plight of sheep and replacing the wool in tennis balls with alternative materials that result in a cruelty-free and high-performing tennis ball suitable for competitive play. We’re presently developing Sheeps certified-vegan tennis balls. However, because the U.S. lacks the capacity for tennis ball production, this effort involves complicated and time-consuming coordination with overseas companies. Because our highest priority is reducing the suffering of sheep, and we aren’t certain when Sheeps balls will be available, we decided to assert ourselves as advocates and seek the most expeditious solution — the production of certified-vegan tennis balls by existing tennis ball companies. And, indeed, if Wilson, Penn, Babolat, Dunlop or another company commits to exclusively producing vegan tennis balls, thereby rendering Sheeps balls unnecessary, we will gladly channel our energy into other projects like developing a biodegradable tennis ball, certified-vegan tennis shoes, and vegan gear for other sports.”
If you are a vegan and play tennis, you may want to join his LinkedIn group as well as his Facebook group. This is what his Care2 petition asks:
“We, the signers of this petition, urge the leading tennis ball manufacturers in the United States to no longer make use of wool in the production of tennis balls — and to instead produce the balls with animal-free materials. By doing so, the leaders of these companies are offered the opportunity to spare a practically countless amount of sheep from exploitation and death, and to contribute profoundly to an ever-growing movement away from the human consumption of animal products and toward a kinder, healthier and a more just and sustainable society. For certain, those among us who play the sport of tennis will be elated to purchase vegan tennis balls, and we will be forever grateful that we may finally play our beloved sport worry-free.”
It would be great if any vegan tennis player, professional or otherwise, could help this campaign. Famous plant-based players such as Venus Williams, Serena Williams, or Novak Djokovic may not care that much about whether there are animal products in their equipment. But perhaps the American Vicki Cosio, who became vegan in 1999 and said she did it for the animals, would. Or the Australian Bernard Tomic, as when he became vegan said he is a believer in karma and “I don’t miss [animal products?] because there are animals involved.” Or the Australian Nick Kyrgios, who became vegan just within the last year or two, as he seemed genuinely distressed about the loss of all the animals in the wildfires in Australia.
Perhaps in addition to investing in fake meats or vegan restaurants, they could invest in research to produce vegan tennis balls. Or perhaps discuss this issue with the major balls manufacturers and sponsors. Wouldn’t that be both nice and consistent? vegan tennis players helping make tennis vegan is something that I would expect. Here are some of their Twitter handlers if you want to suggest that to them directly: @BernardTomicAU, @NickKyrgios.
I don’t play tennis, but I am wondering if there are any vegan tennis players in the UK (playing competitively) who perhaps could help too. They may be in a better position to ask their tennis clubs or tournament organisers if they can provide them with vegan tennis balls. I am saying specifically UK players because, since 2020, ethical veganism has become a protected philosophical belief in Great Britain, and therefore perhaps they may be more successful in their request if they point this out.
What About my Ball?
It was time to find out whether the ball I had at home was vegan. I showed it to Danny during the Zoom call. He looked at it and said that it was probably not vegan. Disappointing indeed.

But in my case, the solution was simple. The next time I went to the park I took the ball there and left it around the area I had found it. I thought a dog would most likely pick it up and adopt it as a new toy — and indeed, it was gone the following day. And when I came back home, I of course signed Danny’s petition (please also do so).
It was easy for me to act on my discovery, but those who love playing tennis competitively would have to face a real dilemma. I don’t think it’s fair that the only choice for them is dropping their beloved sport from their lives as I dropped the ball in the park. They should be able to enjoy it as anyone else, without feeling they are contributing to animal suffering. And the same applies to any other sport or hobby.
We all should get inspired by Danny’s attitude and rather than move away from the problem, get even closer trying to solve it. Research what’s there, research for what is not there yet, try to make the changes yourself, and if that doesn’t work try to persuade others in a much better position to make them.
By not quitting his sport for not being vegan enough Danny could perhaps one day achieve his goal. For him, and all vegan tennis players. For them, and all the unfortunate sheep force to give their hair for the sport.
If we help him, he could make tennis vegan. We all can.