Modern dolphin

<div class="loader"></div>

/* From Uiverse.io by bernethe - Tags: loader */
.loader {
  width: 2rem;
  height: 2rem;
  clear: both;
  margin: 1rem auto;
  border-radius: 50%;
  border-left: 0 #000 solid;
  border-right: 0 #000 solid;
  animation: spSphere 1s infinite linear;
}

@keyframes spSphere {
  0% {
    border-left: 0 #000 solid;
    border-right: 0 #000 solid;
  }

  33% {
    border-left: 2rem #000 solid;
    border-right: 0 #000 solid;
  }

  34% {
    border-left: 0 #000 solid;
    border-right: 2rem #000 solid;
  }

  66% {
    border-left: 0 #000 solid;
    border-right: 0 #000 solid;
  }
}

<div class="loader"></div>
<style>
/* From Uiverse.io by bernethe - Tags: loader */
.loader {
  width: 2rem;
  height: 2rem;
  clear: both;
  margin: 1rem auto;
  border-radius: 50%;
  border-left: 0 #000 solid;
  border-right: 0 #000 solid;
  animation: spSphere 1s infinite linear;
}

@keyframes spSphere {
  0% {
    border-left: 0 #000 solid;
    border-right: 0 #000 solid;
  }

  33% {
    border-left: 2rem #000 solid;
    border-right: 0 #000 solid;
  }

  34% {
    border-left: 0 #000 solid;
    border-right: 2rem #000 solid;
  }

  66% {
    border-left: 0 #000 solid;
    border-right: 0 #000 solid;
  }
}

</style>