One of the first questions people ask when buying a jumping spider is "should I get a male or a female?" The honest answer is that both make good pets, but the differences between them are real and worth understanding before you choose. Sexual dimorphism in jumping spiders is pronounced enough that males and females can look like completely different species.
How they look
In most Phidippus species, the differences are obvious once you know what to look for. Take P. regius as an example:
Females are the larger sex. Adult females reach 15-22mm body length and tend to be grey, tan, or brownish with lighter patterning on the abdomen. Some show orange or reddish tones depending on the locality or colour form. They're chunky, especially when well-fed, with a noticeably bigger abdomen than males.
Males are smaller, typically 12-15mm body length. They're often jet black with white lateral bands and spots on the abdomen. The real showpiece is the chelicerae, which in many males are a vivid iridescent green. They're slimmer and more leggy-looking than females, with proportionally larger pedipalps that develop bulbous tips at maturity (the palpal organs, used for mating).
The pattern holds across other commonly kept species. Male P. audax are darker with more contrasting markings. In Hyllus diardi, males develop longer, more prominent chelicerae. Males across the Salticidae tend towards more striking colouration than females, which makes evolutionary sense given that their courtship involves complex visual displays.
Behaviour differences
This is where generalising gets tricky, because individual personality variation often outweighs sex-based differences. That said, some patterns do exist.
Males tend to be more active and restless once they reach maturity. In the wild, adult males spend much of their time wandering in search of females. In captivity, this translates to a spider that paces its enclosure more, seems less content to sit still, and sometimes appears "stressed" when really it's just following a biological drive to move. Some keepers find mature males harder to handle because they won't sit still.
Females are generally calmer and more sedentary, particularly mature females. They'll establish a retreat and spend more of their time near it. They tend to be more predictable during handling sessions, which makes them the easier choice if handling is a priority for you.
Both sexes are equally curious. The head-tilting, tracking-your-finger, investigating-new-objects behaviour that makes jumping spiders so appealing is present regardless of sex.
Lifespan
This is the big one. Female jumping spiders live significantly longer than males. For P. regius, females typically live 1-2 years while males live around 6-12 months post-maturity. Males also mature faster, so the total lifespan from hatching to death is shorter on both ends.
If you're buying a sub-adult or adult male, understand that you might only have a few months with it. That's not a reason to avoid males, just something to go in with your eyes open about.
How to tell them apart
Sexing juvenile jumping spiders is difficult. Until about the fourth or fifth instar, males and females look quite similar. As they approach maturity, differences start appearing:
- Pedipalps. This is the most reliable method. Male pedipalps develop bulbous, club-like tips as they mature. Females have slender, leg-like pedipalps throughout life. By the penultimate instar, the difference is usually visible to the naked eye.
- Colouration. Males start developing their darker adult colouration earlier than the final moult. A juvenile P. regius that's turning noticeably black is likely male. Not infallible, but a reasonable indicator.
- Body shape. Sub-adult males start looking leggier and slimmer than females of the same instar. Females develop a rounder, wider abdomen.
- Moult examination. If you can retrieve an exuviae (shed skin), you can examine the ventral abdomen under magnification. Females will show the developing epigynal area. This is the most reliable method but requires a decent magnifying glass or macro lens and some practice.
Very young slings are essentially impossible to sex visually. If a seller tells you they can sex a second-instar jumper by eye, be sceptical.
Breeding considerations
If you're keeping both males and females, a word on breeding: jumping spiders are solitary animals. You cannot house a male and female together permanently. The female will eventually eat the male, and sometimes she'll skip the mating part entirely.
Breeding introductions should be brief and supervised. The male performs an elaborate courtship dance involving leg waving, body vibrations, and display of his colourful markings. If the female is receptive, mating occurs. If she's not, she may attack. Have a way to separate them quickly. A piece of card slid between them works.
Breeding jumping spiders is rewarding but produces a lot of slings. A single egg sac from a P. regius can contain 50-200 eggs. Be sure you have a plan for that many spiderlings before you start.
So which should you get?
For a first spider: a female, probably. Longer lifespan, calmer temperament, more forgiving of handling mistakes. But males are gorgeous animals in their own right, and if you're drawn to those iridescent chelicerae and dramatic black-and-white patterning, go for it. Just know the timeline is shorter.